DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Information Disclosure Statement
The information disclosure statements (IDS) submitted on 12/5/2024 and 12/03/2025 are being considered by the examiner.
Claim Rejections - 35 USC § 112
The following is a quotation of the first paragraph of 35 U.S.C. 112(a):
(a) IN GENERAL.—The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor or joint inventor of carrying out the invention.
The following is a quotation of the first paragraph of pre-AIA 35 U.S.C. 112:
The specification shall contain a written description of the invention, and of the manner and process of making and using it, in such full, clear, concise, and exact terms as to enable any person skilled in the art to which it pertains, or with which it is most nearly connected, to make and use the same, and shall set forth the best mode contemplated by the inventor of carrying out his invention.
Claims 10 and 11 are rejected under 35 U.S.C. 112(a) or 35 U.S.C. 112 (pre-AIA ), first paragraph, as failing to comply with the written description requirement. The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
1). Claim 10 recites the limitations “wherein determining the second decoder value comprises comparing the approximate phase profile with ideal approximate phase profiles”. However, the Specification does not clearly define “ideal approximate phase profiles”, and the Specification does not clearly describe what the “ideal approximate phase profiles” are. In paragraph [0089], Applicant defines a Π(t), a Π0(t) and Π1(t); and in paragraph [0174], the Specification states “the ideal approximate phase profiles {Πa(t)}t (comprising ideal phase values Πa(t)) and determining the second decoder value by comparing the second measured correlator difference ΔR with the second threshold value ΔR̄”. But, the Specification does not define a Πa(t); and the Specification does not specify how the ideal approximate phase profiles are obtained or calculated.
2). Claim 11 recites the limitations “determining a second measured correlator difference from the approximate phase profile and the ideal approximate phase profiles and determining the second decoder value by comparing the second measured correlator difference with a second threshold value”. However, the Specification does not clearly define “ideal approximate phase profiles”, and the Specification does not clearly describe what the “ideal approximate phase profiles” are. In paragraph [0089], Applicant defines a Π(t), a Π0(t) and Π1(t); and in paragraph [00174], the Specification states “the ideal approximate phase profiles {Πa(t)}t (comprising ideal phase values Πa(t)) and determining the second decoder value by comparing the second measured correlator difference ΔR with the second threshold value ΔR̄”. But, the Specification does not define a Πa(t); and the Specification does not specify how the ideal approximate phase profiles are obtained or calculated.
The claim(s) contains subject matter which was not described in the specification in such a way as to reasonably convey to one skilled in the relevant art that the inventor or a joint inventor, or for applications subject to pre-AIA 35 U.S.C. 112, the inventor(s), at the time the application was filed, had possession of the claimed invention.
The following is a quotation of 35 U.S.C. 112(b):
(b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention.
The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claim 11 is rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention.
Claim 11 recites the limitations “the ideal approximate intensity profiles” in line 3 and "the ideal approximate phase profiles" in line 7. There is insufficient antecedent basis for these limitations in the claim.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claims 1-3, 7, 9-10 and 12-17 are rejected under 35 U.S.C. 103 as being unpatentable over Tanaka et al (JP 2011188043 A) in view of Lesovik et al (US 2022/0271928).
1). With regard to claim 1, Tanaka et al discloses an encoding method for quantum key distribution ([0002]-[00011], [0023]-[0024] and [0103], quantum key distribution, QKD, system/method), the method being carried out in a transmitter device (e.g., Alice 10 in Figure 1, 5 and 10; also 70 in Figure 7; and Alice in Figure 11) having a classical processor (107 etc., [0028] and [0033]-[0034], [0037], [0046] and [0059] etc.) and instrumentalities (101-107 etc.) for preparing and transmitting quantum signals (the output from the modulator 104), the method comprising:
generating an encoder initial bit sequence (e.g., from random number source 106);
generating, from the encoder initial bit sequence, a quantum signal (the output from the modulator 104) comprising a plurality of optical pulses ([0027]-[0029] etc., and Figures 2-3, 11 and 13 etc.), wherein generating each optical pulse of the plurality of optical pulses comprises at least one of:
modulating an intensity profile of the optical pulse according to an intensity function which depends on a time and on a first encoder value of at least one first bit of the encoder initial bit sequence (note: in the Specification, para [0187], Applicant states “The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context”; Tanaka et al discloses a phase modulator 104, no intensity modulator; since “at least one of modulating an intensity profile … and modulating a phase profile” is construed to mean one item selected from the listed items (phase modulation or intensity modulation), Tanaka et al reads on applicant’s claim limitations even only a phase modulation is present); and
modulating a phase profile (by the phase modulator 104) of the optical pulse according to a phase function ([0027], “adds a predetermined phase difference to the two time-separated photon pulses”) which depends on a time ([0027] and [0031], “the phase modulator 104 modulates the optical phase of one of the two optical pulses according to a random number from the random number source 106, thereby randomly changing the relative phase difference (φ A) of the two optical pulses to four possibilities”) and a second encoder value (e.g., the each pulse has a different encode value, e.g., “1” or “0”; [0011]-[0012], “in a quantum cryptographic key distribution method that codes four states using the phase difference between two coherent pulses, a coding set (hereinafter referred to as "X basis") is defined as a pair where phase 0 represents cryptographic key "0" and phase π represents cryptographic key "1".) and a coding set (hereinafter referred to as the "Y basis") in which phase π/2 represents encryption key "0" and phase 3π/2 represents encryption key "1". ) and are selected as two sets of bases using random numbers 2. In other words, for each photon, four different modulations - 0, π/2, π, and 3π/2 - are randomly applied and then transmitted to Bob1013”) of at least one second bit of the encoder initial bit sequence ([0006], “The two-pulse transmission train 1003 is transmitted to the Bob side through the optical transmission path. In the most representative quantum cryptography key distribution algorithm, known as the BB84 protocol (described later), φA takes on four values: 0, π/2, π, and 3π/2, and these four values are randomly assigned to each pulse pair”; [0011], “for each photon, four different modulations—0, π/2, π, and 3π/2—are randomly applied and then transmitted to Bob1013”. The two second bits of the encoder initial bit sequence are the second pair of bits from the asymmetric optical interferometer 102; [0027], “an asymmetric optical interferometer 102 that outputs a double pulse by time-separating the photon pulses”. Figures 11-13 etc.);
transmitting the plurality of optical pulses to a receiver device via a quantum channel ([0026]-[0027], the optical transmission line 30); and
determining a shared key shared between the transmitter device and the receiver device ([0038], “the final encryption key is shared between Alice10 and Bob20”. And, [0002]-[0011], [0023]-[0024] and [0103], quantum key distribution QKD; and [0033]) from the encoder initial bit sequence by classical post-processing and at least one of transmitting classical information to the receiver device ([0037], “Once frame synchronization is established, the base matching process S1102 and S2102 then proceed, with the processor 107 and processor 207 exchanging base matching data and matching results to perform base matching (see Figure 12). If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits; however, if the bases are different, Bob20 will obtain random values for the detected bits”. And by the key generation process, [0028], [0030] and [0033]).
But, Tanaka et al does not expressly disclose: receiving further classical information from the receiver device.
However, to exchange classical information between two processing device is known in the art. E.g., Lesovik et al discloses a system/method to for quantum key distribution includes determining an intrinsic loss along a quantum channel (Figures 1-2, 4 and 8 etc.), and Lesovik et al discloses “The first data processing device and the second data processing device may exchange classical signals via the public channel. Classical signals may also be exchanged via the quantum channel. The optical fiber may be shared by the quantum channel and the classical channel. Alternatively, the quantum channel and the classical channel may be separate” ([0025]), and “The first data processing device 10 and the second data processing device 11 can further exchange classical signals, in particular via a public channel 14. Classical signals may also be exchanged via the quantum channel 13. The optical fibre may be shared by the quantum channel 13 and the classical channel. Alternatively, the quantum channel and the classical channel can be physically separate” ([0072]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Lesovik et al to the system/method of Tanaka et al so that the two data processing device can exchange classical information, and the functions of the system/method are enhanced.
2). With regard to claim 2, Tanaka et al and Lesovik et al disclose all of the subject matter as applied to claim 1 above. And the combination of Tanaka et al and Lesovik et al further discloses wherein each optical pulse is generated from a laser beam (Tanaka: 101) and using a Mach-Zehnder interferometer (Tanaka:102. Also refer Figures ).
3). With regard to claim 3, Tanaka et al and Lesovik et al disclose all of the subject matter as applied to claim 1 above. And the combination of Tanaka et al and Lesovik et al further discloses wherein the intensity profile is modulated by at least one of a first phase modulator and a laser source intensity; and/or wherein the phase profile is modulated by a second phase modulator (Tanaka: 104).
4). With regard to claim 7, Tanaka et al and Lesovik et al disclose all of the subject matter as applied to claim 1 above. And the combination of Tanaka et al and Lesovik et al further discloses wherein the intensity function depends on the first encoder value of at least two first bits of the encoder initial bit sequence; and/or wherein the phase function depends on the second encoder value of at least two second bits of the encoder initial bit sequence ([0006], “The two-pulse transmission train 1003 is transmitted to the Bob side through the optical transmission path. In the most representative quantum cryptography key distribution algorithm, known as the BB84protocol (described later), φA takes on four values: 0, π/2, π, and 3π/2, and these four values are randomly assigned to each pulse pair”; [0011], “for each photon, four different modulations—0, π/2, π, and 3π/2—are randomly applied and then transmitted to Bob1013”. The two second bits of the encoder initial bit sequence are the second pair of bits from the asymmetric optical interferometer 102; [0027], “an asymmetric optical interferometer 102 that outputs a double pulse by time-separating the photon pulses”. Figures 11-13 etc.).
5). With regard to claim 9, Tanaka et al discloses a decoding method for quantum key distribution ([0002]-[00011], [0023]-[0024] and [0103], quantum key distribution, QKD, system/method), the method being carried out in a receiver device (e.g., Bob 20 in Figure 1, 5 and 10; also 80 in Figure 7; and Bob in Figure 11) having a classical processor (207 etc., [0028] and [0033]-[0034], [0037] and [0078] etc.) and instrumentalities (201-207 etc.) for receiving and measuring quantum signals (received by the modulator 201), the method comprising:
receiving a quantum signal (received by the modulator 201) comprising a plurality of optical pulses (Figures 2-3 and 11-13) from a transmitter device (e.g., Alice 10 in Figure 1, 5 and 10; also 70 in Figure 7; and Alice in Figure 11) via a quantum channel ([0026]-[0027], the optical transmission line 30);
determining a decoder initial bit sequence from the plurality of optical pulses ([0037], “Once frame synchronization is established, the base matching process S1102 and S2102 then proceed, with the processor 107 and processor 207 exchanging base matching data and matching results top perform base matching (see Figure 12). If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits”), the determining comprising, for each optical pulse, at least one of:
determining an approximate intensity profile of the optical pulse by measuring a plurality of intensity values of the optical pulse for a plurality of time bins, and determining, from the approximate intensity profile, a first decoder value of at least one first bit of the decoder initial bit sequence (note: in the Specification, para [0187], Applicant states “The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context”; Tanaka et al discloses a phase modulator 201 for determining phase profile; since “at least one of determining an approximate intensity profile … and determining an approximate phase profile” is construed to mean one item selected from the listed items (determining an approximate intensity profile or determining an approximate phase profile), Tanaka et al reads on applicant’s claim limitations even only a phase modulation is present), and
determining an approximate phase profile of the optical pulse by measuring a plurality of phase values of the optical pulse for a plurality of time bins ([0029], “Bob 20 includes a phase modulator 201 that again applies a phase difference to the twin photon pulse sent from Alice 10 through the optical transmission path 30, a Mach-Zehnder interferometer 202 that combines the twin photon pulses, a temperature controller 203 (here a thermoelectric cooler TEC) for adjusting the delay amount of the Mach-Zehnder interferometer 202, two gate-mode photon detectors204 and 205 that are optically connected to the two output ports port1 and port2 of the Mach-Zehnder interferometer 202, respectively, and a random number source 206 that supplies random numbers to the mobile modulator 201”; [0032], “The phase modulator 201 of Bob 20 modulates the optical phase of one of the arriving double optical pulses. In this case, phase modulation is performed randomly so that the relative phase difference (φB) of the two optical pulses is 0 or π/2.These two optical pulses are combined by passing through the Mach-Zehnder interferometer 202, and photon detectors 204 and 205 connected to port 1 and port 2, respectively, detect the interference results according to the modulation phases applied to Alice 10 and Bob 20, respectively”; [0037], “If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits; however, if the bases are different, Bob20 will obtain random values for the detected bits”; Figure 12), and determining, from the approximate phase profile, a second decoder value (e.g., the each pulse has a different encode value, e.g., “1” or “0”; [0011]-[0012], “in a quantum cryptographic key distribution method that codes four states using the phase difference between two coherent pulses, a coding set (hereinafter referred to as "X basis") is defined as a pair where phase 0 represents cryptographic key "0" and phase π represents cryptographic key "1".) and a coding set (hereinafter referred to as the "Y basis") in which phase π/2 represents encryption key "0" and phase 3π/2 represents encryption key "1". ) and are selected as two sets of bases using random numbers 2. In other words, for each photon, four different modulations - 0, π/2, π, and 3π/2 - are randomly applied and then transmitted to Bob1013”) of at least one second bit of the decoder initial bit sequence ([0006], “The two-pulse transmission train 1003 is transmitted to the Bob side through the optical transmission path. In the most representative quantum cryptography key distribution algorithm, known as the BB84 protocol (described later), φA takes on four values: 0, π/2, π, and 3π/2, and these four values are randomly assigned to each pulse pair”; [0011], “for each photon, four different modulations—0, π/2, π, and 3π/2—are randomly applied and then transmitted to Bob1013”. The two second bits of the encoder initial bit sequence are the second pair of bits from the asymmetric optical interferometer 102; [0027], “an asymmetric optical interferometer 102 that outputs a double pulse by time-separating the photon pulses”. Figures 11-13 etc.); and
determining a shared key shared between the transmitter device and the receiver device ([0038], “the final encryption key is shared between Alice10 and Bob20”. And, [0002]-[0011], [0023]-[0024] and [0103], quantum key distribution QKD; and [0033]) from the decoder initial bit sequence (Figures 11-13 etc.) by classical post-processing (207 etc.) and at least one of receiving classical information from the transmitter device ([0037], “Once frame synchronization is established, the base matching process S1102 and S2102 then proceed, with the processor 107 and processor 207 exchanging base matching data and matching results to perform base matching (see Figure 12). If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits; however, if the bases are different, Bob20 will obtain random values for the detected bits”. And by the key generation process, [0028], [0030] and [0033]) and receiving further classical information from the receiver device ([0034] and [0037]-[0038], [0101]; “If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits”) and
But, Tanaka et al does not expressly disclose: transmitting further classical information to the transmitter device.
But, to exchange classical information between two processing device is known in the art. E.g., Lesovik et al discloses a system/method to for quantum key distribution includes determining an intrinsic loss along a quantum channel (Figures 1-2, 4 and 8 etc.), and Lesovik et al discloses “The first data processing device and the second data processing device may exchange classical signals via the public channel. Classical signals may also be exchanged via the quantum channel. The optical fiber may be shared by the quantum channel and the classical channel. Alternatively, the quantum channel and the classical channel may be separate” ([0025]), and “The first data processing device 10 and the second data processing device 11 can further exchange classical signals, in particular via a public channel 14. Classical signals may also be exchanged via the quantum channel 13. The optical fibre may be shared by the quantum channel 13 and the classical channel. Alternatively, the quantum channel and the classical channel can be physically separate” ([0072]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Lesovik et al to the system/method of Tanaka et al so that the two data processing device can exchange classical information, and the functions of the system/method are enhanced.
6). With regard to claim 10, Tanaka et al and Lesovik et al disclose all of the subject matter as applied to claim 9 above. But, Tanaka et al and Lesovik et al do not expressly disclose wherein determining the first decoder value comprises comparing the approximate intensity profile with ideal approximate intensity profiles; and/or wherein determining the second decoder value comprises comparing the approximate phase profile with ideal approximate phase profiles (also refer to the 112 rejection above).
However, Tanaka et al discloses “By obtaining an output of 0 or 1 based on this difference in modulation phase depth, and then comparing a portion of the conditions under which the output data was measured between Alice and Bob, it is ultimately possible to share the same bit sequence between Alice and Bob” ([0004]), “determines the detection signal S0 from the balanced photodetector 806 by comparing itwith the threshold levels. As will be described later, it divides the signal into a confirmed determination signal and a provisional determination signal and outputs them to the processor 801.Similarly, the multi-level discrimination circuit 809 maintains three threshold levels L0, L1, and L2, and determines the detection signal S1 from the balanced photodetector 807 by comparing it with the threshold levels” ([0067]), “adjusts the delay amount of the interference means based on a comparison of the error rate with a predetermined reference value” ([0082] and [0089] [0095]). That is, Tanaka et al discloses a scheme to compare a detected signal with a with another predetermined value. Therefore, it is obvious to one skilled in the art based on the teaching of Tanaka to compare the approximate phase profile with ideal approximate phase profiles so to accurately and properly determine the second decoder value.
7). With regard to claim 12, Tanaka et al and Lesovik et al disclose all of the subject matter as applied to claim 9 above. And the combination of Tanaka et al and Lesovik et al further discloses the method according to claim 9, further comprising determining optical signal losses along the quantum channel (Lesovik: Abstract etc. “system and method for quantum key distribution includes determining an intrinsic loss along a quantum channel”).
8). With regard to claim 13, Tanaka et al and Lesovik et al disclose all of the subject matter as applied to claims 9 and 12 above. And the combination of Tanaka et al and Lesovik et al further discloses wherein the optical signal losses depend on a position along the quantum channel (Lesovik: Figure 7 etc.).
9). With regard to claim 14, Tanaka et al discloses a method for quantum key distribution ([0002]-[00011], [0023]-[0024] and [0103], quantum key distribution, QKD, system/method), the method being carried out in a system comprising a transmitter device (e.g., Alice 10 in Figure 1, 5 and 10; also 70 in Figure 7; and Alice in Figure 11) having a classical processor (107 etc., [0028] and [0033]-[0034], [0037], [0046] and [0059] etc.) and instrumentalities (101-107 etc.) for preparing and transmitting quantum signals (the output from the modulator 104); and a receiver device (e.g., Bob 20 in Figure 1, 5 and 10; also 80 in Figure 7; and Bob in Figure 11) having a further classical processor (207 etc., [0028] and [0033]-[0034], [0037] and [0078] etc.) and instrumentalities (201-207 etc.) for receiving and measuring quantum signals (received by the modulator 201), the method comprising:
generating an encoder initial bit sequence (e.g., from random number source 106) in the transmitter device;
generating, from the encoder initial bit sequence, a quantum signal (the output from the modulator 104) comprising a plurality of optical pulses ([0027]-[0029] etc., and Figures 2-3, 11 and 13 etc.) in the transmitter device, wherein generating each optical pulse of the plurality of optical pulses comprises at least one of:
modulating an intensity profile of the optical pulse according to an intensity function which depends on a time and on a first encoder value of at least one first bit of the encoder initial bit sequence (note: in the Specification, para [0187], Applicant states “The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context”; Tanaka et al discloses a phase modulator 104, no intensity modulator; since “at least one of modulating an intensity profile … and modulating a phase profile” is construed to mean one item selected from the listed items (phase modulation or intensity modulation), Tanaka et al reads on applicant’s claim limitations even only a phase modulation is present) and
modulating a phase profile (by the phase modulator 104) of the optical pulse according to a phase function ([0027], “adds a predetermined phase difference to the two time-separated photon pulses”) which depends on a time ([0027] and [0031], “the phase modulator 104 modulates the optical phase of one of the two optical pulses according to a random number from the random number source 106, thereby randomly changing the relative phase difference (φ A) of the two optical pulses to four possibilities”) and a second encoder value (e.g., the each pulse has a different encode value, e.g., “1” or “0”; [0011]-[0012], “in a quantum cryptographic key distribution method that codes four states using the phase difference between two coherent pulses, a coding set (hereinafter referred to as "X basis") is defined as a pair where phase 0 represents cryptographic key "0" and phase π represents cryptographic key "1".) and a coding set (hereinafter referred to as the "Y basis") in which phase π/2 represents encryption key "0" and phase 3π/2 represents encryption key "1". ) and are selected as two sets of bases using random numbers 2. In other words, for each photon, four different modulations - 0, π/2, π, and 3π/2 - are randomly applied and then transmitted to Bob1013”) of at least one second bit of the encoder initial bit sequence ([0006], “The two-pulse transmission train 1003 is transmitted to the Bob side through the optical transmission path. In the most representative quantum cryptography key distribution algorithm, known as the BB84 protocol (described later), φA takes on four values: 0, π/2, π, and 3π/2, and these four values are randomly assigned to each pulse pair”; [0011], “for each photon, four different modulations—0, π/2, π, and 3π/2—are randomly applied and then transmitted to Bob1013”. The two second bits of the encoder initial bit sequence are the second pair of bits from the asymmetric optical interferometer 102; [0027], “an asymmetric optical interferometer 102 that outputs a double pulse by time-separating the photon pulses”. Figures 11-13 etc.);
transmitting the plurality of optical pulses from the transmitter device to the receiver device via a quantum channel ([0026]-[0027], the optical transmission line 30) and receiving the plurality of optical pulses in the receiver device (received by the modulator 201);
determining a decoder initial bit sequence from the plurality of optical pulses ([0037], “Once frame synchronization is established, the base matching process S1102 and S2102 then proceed, with the processor 107 and processor 207 exchanging base matching data and matching results top perform base matching (see Figure 12). If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits”), the determining comprising for each optical pulse at least one of:
determining an approximate intensity profile of the optical pulse by measuring a plurality of intensity values of the optical pulse for a plurality of time bins, and determining, from the approximate intensity profile, a first decoder value of at least one first bit of the decoder initial bit sequence (note: in the Specification, para [0187], Applicant states “The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context”; Tanaka et al discloses a phase modulator 201 for determining phase profile; since “at least one of determining an approximate intensity profile … and determining an approximate phase profile” is construed to mean one item selected from the listed items (determining an approximate intensity profile or determining an approximate phase profile), Tanaka et al reads on applicant’s claim limitations even only a phase modulation is present); and
determining an approximate phase profile of the optical pulse by measuring a plurality of phase values of the optical pulse for a plurality of time bins ([0029], “Bob 20 includes a phase modulator 201 that again applies a phase difference to the twin photon pulse sent from Alice 10 through the optical transmission path 30, a Mach-Zehnder interferometer 202 that combines the twin photon pulses, a temperature controller 203 (here a thermoelectric cooler TEC) for adjusting the delay amount of the Mach-Zehnder interferometer 202, two gate-mode photon detectors204 and 205 that are optically connected to the two output ports port1 and port2 of the Mach-Zehnder interferometer 202, respectively, and a random number source 206 that supplies random numbers to the mobile modulator 201”; [0032], “The phase modulator 201 of Bob 20 modulates the optical phase of one of the arriving double optical pulses. In this case, phase modulation is performed randomly so that the relative phase difference (φB) of the two optical pulses is 0 or π/2.These two optical pulses are combined by passing through the Mach-Zehnder interferometer 202, and photon detectors 204 and 205 connected to port 1 and port 2, respectively, detect the interference results according to the modulation phases applied to Alice 10 and Bob 20, respectively”; [0037], “If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits; however, if the bases are different, Bob20 will obtain random values for the detected bits”; Figure 12), and determining, from the approximate phase profile, a second decoder value (e.g., the each pulse has a different encode value, e.g., “1” or “0”; [0011]-[0012], “in a quantum cryptographic key distribution method that codes four states using the phase difference between two coherent pulses, a coding set (hereinafter referred to as "X basis") is defined as a pair where phase 0 represents cryptographic key "0" and phase π represents cryptographic key "1".) and a coding set (hereinafter referred to as the "Y basis") in which phase π/2 represents encryption key "0" and phase 3π/2 represents encryption key "1". ) and are selected as two sets of bases using random numbers 2. In other words, for each photon, four different modulations - 0, π/2, π, and 3π/2 - are randomly applied and then transmitted to Bob1013”) of at least one second bit of the decoder initial bit sequence ([0006], “The two-pulse transmission train 1003 is transmitted to the Bob side through the optical transmission path. In the most representative quantum cryptography key distribution algorithm, known as the BB84 protocol (described later), φA takes on four values: 0, π/2, π, and 3π/2, and these four values are randomly assigned to each pulse pair”; [0011], “for each photon, four different modulations—0, π/2, π, and 3π/2—are randomly applied and then transmitted to Bob1013”. The two second bits of the encoder initial bit sequence are the second pair of bits from the asymmetric optical interferometer 102; [0027], “an asymmetric optical interferometer 102 that outputs a double pulse by time-separating the photon pulses”. Figures 11-13 etc.); and
determining, in the transmitter device from the encoder initial bit sequence and in the receiver device from the decoder initial bit sequence, by classical post-processing (107 and 207) and at least one of transmitting classical information (generated from random number source 106 and modulated by modulator 104) from the transmitter device to the receiver device ([0037], “Once frame synchronization is established, the base matching process S1102 and S2102 then proceed, with the processor 107 and processor 207 exchanging base matching data and matching results to perform base matching (see Figure 12). If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits; however, if the bases are different, Bob20 will obtain random values for the detected bits”. And by the key generation process, [0028], [0030] and [0033]), a shared key shared between the transmitter device and the receiver device ([0038], “the final encryption key is shared between Alice10 and Bob20”. And, [0002]-[0011], [0023]-[0024] and [0103], quantum key distribution QKD; and [0033]).
But, Tanaka et al does not expressly disclose: transmitting further classical information from the receiver device to the transmitter device.
However, to exchange classical information between two processing device is known in the art. E.g., Lesovik et al discloses a system/method to for quantum key distribution includes determining an intrinsic loss along a quantum channel (Figures 1-2, 4 and 8 etc.), and Lesovik et al discloses “The first data processing device and the second data processing device may exchange classical signals via the public channel. Classical signals may also be exchanged via the quantum channel. The optical fiber may be shared by the quantum channel and the classical channel. Alternatively, the quantum channel and the classical channel may be separate” ([0025]), and “The first data processing device 10 and the second data processing device 11 can further exchange classical signals, in particular via a public channel 14. Classical signals may also be exchanged via the quantum channel 13. The optical fibre may be shared by the quantum channel 13 and the classical channel. Alternatively, the quantum channel and the classical channel can be physically separate” ([0072]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Lesovik et al to the system/method of Tanaka et al so that the two data processing device can exchange classical information, and the functions of the system/method are enhanced.
10). With regard to claim 15, Tanaka et al discloses a transmitter device (e.g., Alice 10 in Figure 1, 5 and 10; also 70 in Figure 7; and Alice in Figure 11) for quantum key distribution ([0002]-[00011], [0023]-[0024] and [0103], quantum key distribution, QKD, system/method) comprising a classical processor (107 etc., [0028] and [0033]-[0034], [0037], [0046] and [0059] etc.) and instrumentalities (101-107 etc.) for preparing and transmitting quantum signals (the output from the modulator 104) and being configured to carry out the following steps:
generating an encoder initial bit sequence (e.g., from random number source 106);
generating, from the encoder initial bit sequence, a quantum signal (the output from the modulator 104) comprising a plurality of optical pulses ([0027]-[0029] etc., and Figures 2-3, 11 and 13 etc.), wherein generating each optical pulse of the plurality of optical pulses comprises at least one of:
modulating an intensity profile of the optical pulse according to an intensity function which depends on a time and on a first encoder value of at least one first bit of the encoder initial bit sequence (note: in the Specification, para [0187], Applicant states “The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context”; Tanaka et al discloses a phase modulator 104, no intensity modulator; since “at least one of modulating an intensity profile … and modulating a phase profile” is construed to mean one item selected from the listed items (phase modulation or intensity modulation), Tanaka et al reads on applicant’s claim limitations even only a phase modulation is present) and
modulating a phase profile (by the phase modulator 104) of the optical pulse according to a phase function ([0027], “adds a predetermined phase difference to the two time-separated photon pulses”) which depends on a time ([0027] and [0031], “the phase modulator 104 modulates the optical phase of one of the two optical pulses according to a random number from the random number source 106, thereby randomly changing the relative phase difference (φ A) of the two optical pulses to four possibilities”) and a second encoder value (e.g., the each pulse has a different encode value, e.g., “1” or “0”; [0011]-[0012], “in a quantum cryptographic key distribution method that codes four states using the phase difference between two coherent pulses, a coding set (hereinafter referred to as "X basis") is defined as a pair where phase 0 represents cryptographic key "0" and phase π represents cryptographic key "1".) and a coding set (hereinafter referred to as the "Y basis") in which phase π/2 represents encryption key "0" and phase 3π/2 represents encryption key "1". ) and are selected as two sets of bases using random numbers 2. In other words, for each photon, four different modulations - 0, π/2, π, and 3π/2 - are randomly applied and then transmitted to Bob1013”) of at least one second bit of the encoder initial bit sequence ([0006], “The two-pulse transmission train 1003 is transmitted to the Bob side through the optical transmission path. In the most representative quantum cryptography key distribution algorithm, known as the BB84 protocol (described later), φA takes on four values: 0, π/2, π, and 3π/2, and these four values are randomly assigned to each pulse pair”; [0011], “for each photon, four different modulations—0, π/2, π, and 3π/2—are randomly applied and then transmitted to Bob1013”. The two second bits of the encoder initial bit sequence are the second pair of bits from the asymmetric optical interferometer 102; [0027], “an asymmetric optical interferometer 102 that outputs a double pulse by time-separating the photon pulses”. Figures 11-13 etc.),
transmitting the plurality of optical pulses to a receiver device via a quantum channel ([0026]-[0027], the optical transmission line 30); and
determining a shared key shared between the transmitter device and the receiver device ([0038], “the final encryption key is shared between Alice10 and Bob20”. And, [0002]-[0011], [0023]-[0024] and [0103], quantum key distribution QKD; and [0033]) from the encoder initial bit sequence by classical post-processing and at least one of transmitting classical information to the receiver device ([0037], “Once frame synchronization is established, the base matching process S1102 and S2102 then proceed, with the processor 107 and processor 207 exchanging base matching data and matching results to perform base matching (see Figure 12). If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits; however, if the bases are different, Bob20 will obtain random values for the detected bits”. And by the key generation process, [0028], [0030] and [0033]).
But, Tanaka et al does not expressly disclose: receiving further classical information from the receiver device.
However, to exchange classical information between two processing device is known in the art. E.g., Lesovik et al discloses a system/method to for quantum key distribution includes determining an intrinsic loss along a quantum channel (Figures 1-2, 4 and 8 etc.), and Lesovik et al discloses “The first data processing device and the second data processing device may exchange classical signals via the public channel. Classical signals may also be exchanged via the quantum channel. The optical fiber may be shared by the quantum channel and the classical channel. Alternatively, the quantum channel and the classical channel may be separate” ([0025]), and “The first data processing device 10 and the second data processing device 11 can further exchange classical signals, in particular via a public channel 14. Classical signals may also be exchanged via the quantum channel 13. The optical fibre may be shared by the quantum channel 13 and the classical channel. Alternatively, the quantum channel and the classical channel can be physically separate” ([0072]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Lesovik et al to the system/method of Tanaka et al so that the two data processing device can exchange classical information, and the functions of the system/method are enhanced.
11). With regard to claim 16, Tanaka et al discloses a receiver device (e.g., Bob 20 in Figure 1, 5 and 10; also 80 in Figure 7; and Bob in Figure 11) for quantum key distribution ([0002]-[00011], [0023]-[0024] and [0103], quantum key distribution, QKD, system/method) comprising a classical processor (207 etc., [0028] and [0033]-[0034], [0037] and [0078] etc.) and instrumentalities (201-207 etc.) for receiving and measuring quantum signals (received by the modulator 201) and being configured to carry out the following steps:
receiving a quantum signal (received by the modulator 201) comprising a plurality of optical pulses (Figures 2-3 and 11-13) from a transmitter device (e.g., Alice 10 in Figure 1, 5 and 10; also 70 in Figure 7; and Alice in Figure 11) via a quantum channel ([0026]-[0027], the optical transmission line 30);
determining a decoder initial bit sequence from the plurality of optical pulses ([0037], “Once frame synchronization is established, the base matching process S1102 and S2102 then proceed, with the processor 107 and processor 207 exchanging base matching data and matching results top perform base matching (see Figure 12). If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits”), the determining comprising for each optical pulse at least one of:
determining an approximate intensity profile of the optical pulse by measuring a plurality of intensity values of the optical pulse for a plurality of time bins and determining, from the approximate intensity profile, a first decoder value of at least one first bit of the decoder initial bit sequence (note: in the Specification, para [0187], Applicant states “The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context”; Tanaka et al discloses a phase modulator 201 for determining phase profile; since “at least one of determining an approximate intensity profile … and determining an approximate phase profile” is construed to mean one item selected from the listed items (determining an approximate intensity profile or determining an approximate phase profile), Tanaka et al reads on applicant’s claim limitations even only a phase modulation is present), and
determining an approximate phase profile of the optical pulse by measuring a plurality of phase values of the optical pulse for a plurality of time bins ([0029], “Bob 20 includes a phase modulator 201 that again applies a phase difference to the twin photon pulse sent from Alice 10 through the optical transmission path 30, a Mach-Zehnder interferometer 202 that combines the twin photon pulses, a temperature controller 203 (here a thermoelectric cooler TEC) for adjusting the delay amount of the Mach-Zehnder interferometer 202, two gate-mode photon detectors204 and 205 that are optically connected to the two output ports port1 and port2 of the Mach-Zehnder interferometer 202, respectively, and a random number source 206 that supplies random numbers to the mobile modulator 201”; [0032], “The phase modulator 201 of Bob 20 modulates the optical phase of one of the arriving double optical pulses. In this case, phase modulation is performed randomly so that the relative phase difference (φB) of the two optical pulses is 0 or π/2.These two optical pulses are combined by passing through the Mach-Zehnder interferometer 202, and photon detectors 204 and 205 connected to port 1 and port 2, respectively, detect the interference results according to the modulation phases applied to Alice 10 and Bob 20, respectively”; [0037], “If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits; however, if the bases are different, Bob20 will obtain random values for the detected bits”; Figure 12) and determining, from approximate phase profile, a second decoder value of at least one second bit of the decoder initial bit sequence (e.g., the each pulse has a different encode value, e.g., “1” or “0”; [0011]-[0012], “in a quantum cryptographic key distribution method that codes four states using the phase difference between two coherent pulses, a coding set (hereinafter referred to as "X basis") is defined as a pair where phase 0 represents cryptographic key "0" and phase π represents cryptographic key "1".) and a coding set (hereinafter referred to as the "Y basis") in which phase π/2 represents encryption key "0" and phase 3π/2 represents encryption key "1". ) and are selected as two sets of bases using random numbers 2. In other words, for each photon, four different modulations - 0, π/2, π, and 3π/2 - are randomly applied and then transmitted to Bob1013”) of at least one second bit of the decoder initial bit sequence ([0006], “The two-pulse transmission train 1003 is transmitted to the Bob side through the optical transmission path. In the most representative quantum cryptography key distribution algorithm, known as the BB84 protocol (described later), φA takes on four values: 0, π/2, π, and 3π/2, and these four values are randomly assigned to each pulse pair”; [0011], “for each photon, four different modulations—0, π/2, π, and 3π/2—are randomly applied and then transmitted to Bob1013”. The two second bits of the encoder initial bit sequence are the second pair of bits from the asymmetric optical interferometer 102; [0027], “an asymmetric optical interferometer 102 that outputs a double pulse by time-separating the photon pulses”. Figures 11-13 etc.); and
determining a shared key shared between the transmitter device and the receiver device ([0038], “the final encryption key is shared between Alice10 and Bob20”. And, [0002]-[0011], [0023]-[0024] and [0103], quantum key distribution QKD; and [0033]) from the decoder initial bit sequence by classical post-processing (207 etc.) and at least one of receiving classical information from the transmitter device ([0037], “Once frame synchronization is established, the base matching process S1102 and S2102 then proceed, with the processor 107 and processor 207 exchanging base matching data and matching results to perform base matching (see Figure 12). If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits; however, if the bases are different, Bob20 will obtain random values for the detected bits”. And by the key generation process, [0028], [0030] and [0033]) and receiving further classical information from the receiver device ([0034] and [0037]-[0038], [0101]; “If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits”).
But, Tanaka et al does not expressly disclose: transmitting further classical information to the transmitter device.
However, to exchange classical information between two processing device is known in the art. E.g., Lesovik et al discloses a system/method to for quantum key distribution includes determining an intrinsic loss along a quantum channel (Figures 1-2, 4 and 8 etc.), and Lesovik et al discloses “The first data processing device and the second data processing device may exchange classical signals via the public channel. Classical signals may also be exchanged via the quantum channel. The optical fiber may be shared by the quantum channel and the classical channel. Alternatively, the quantum channel and the classical channel may be separate” ([0025]), and “The first data processing device 10 and the second data processing device 11 can further exchange classical signals, in particular via a public channel 14. Classical signals may also be exchanged via the quantum channel 13. The optical fibre may be shared by the quantum channel 13 and the classical channel. Alternatively, the quantum channel and the classical channel can be physically separate” ([0072]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Lesovik et al to the system/method of Tanaka et al so that the two data processing device can exchange classical information, and the functions of the system/method are enhanced.
12). With regard to claim 17, Tanaka et al discloses a system (Figure 1, 5 and 10 etc.) for quantum key distribution ([0002]-[00011], [0023]-[0024] and [0103], quantum key distribution, QKD, system/method), comprising a transmitter device (e.g., Alice 10 in Figure 1, 5 and 10; also 70 in Figure 7; and Alice in Figure 11) having a classical processor (107 etc., [0028] and [0033]-[0034], [0037], [0046] and [0059] etc.) and means (101-107 etc.) for preparing and transmitting quantum signals (the output from the modulator 104); and a receiver device (e.g., Bob 20 in Figure 1, 5 and 10; also 80 in Figure 7; and Bob in Figure 11) having a further classical processor (207 etc., [0028] and [0033]-[0034], [0037] and [0078] etc.) and means (201-207 etc.) for receiving and measuring quantum signals (received by the modulator 201), the system being configured to carry out the following steps:
generating an encoder initial bit sequence (e.g., from random number source 106) in the transmitter device;
generating, from the first initial bit sequence, a quantum signal (the output from the modulator 104) comprising a plurality of optical pulses ([0027]-[0029] etc., and Figures 2-3, 11 and 13 etc.) in the transmitter device, wherein generating each optical pulse of the plurality of optical pulses comprises at least one of:
modulating an intensity profile of the optical pulse according to an intensity function which depends on a time and on a first encoder value of at least one first bit of the encoder initial bit sequence (note: in the Specification, para [0187], Applicant states “The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context”; Tanaka et al discloses a phase modulator 104, no intensity modulator; since “at least one of modulating an intensity profile … and modulating a phase profile” is construed to mean one item selected from the listed items (phase modulation or intensity modulation), Tanaka et al reads on applicant’s claim limitations even only a phase modulation is present); and
modulating a phase profile (by the phase modulator 104) of the optical pulse according to a phase function ([0027], “adds a predetermined phase difference to the two time-separated photon pulses”) which depends on a time ([0027] and [0031], “the phase modulator 104 modulates the optical phase of one of the two optical pulses according to a random number from the random number source 106, thereby randomly changing the relative phase difference (φ A) of the two optical pulses to four possibilities”) and a second encoder value (e.g., the each pulse has a different encode value, e.g., “1” or “0”; [0011]-[0012], “in a quantum cryptographic key distribution method that codes four states using the phase difference between two coherent pulses, a coding set (hereinafter referred to as "X basis") is defined as a pair where phase 0 represents cryptographic key "0" and phase π represents cryptographic key "1".) and a coding set (hereinafter referred to as the "Y basis") in which phase π/2 represents encryption key "0" and phase 3π/2 represents encryption key "1". ) and are selected as two sets of bases using random numbers 2. In other words, for each photon, four different modulations - 0, π/2, π, and 3π/2 - are randomly applied and then transmitted to Bob1013”) of at least one second bit of the encoder initial bit sequence ([0006], “The two-pulse transmission train 1003 is transmitted to the Bob side through the optical transmission path. In the most representative quantum cryptography key distribution algorithm, known as the BB84 protocol (described later), φA takes on four values: 0, π/2, π, and 3π/2, and these four values are randomly assigned to each pulse pair”; [0011], “for each photon, four different modulations—0, π/2, π, and 3π/2—are randomly applied and then transmitted to Bob1013”. The two second bits of the encoder initial bit sequence are the second pair of bits from the asymmetric optical interferometer 102; [0027], “an asymmetric optical interferometer 102 that outputs a double pulse by time-separating the photon pulses”. Figures 11-13 etc.),
transmitting the plurality of optical pulses from the transmitter device to the receiver device via a quantum channel ([0026]-[0027], the optical transmission line 30) and receiving the plurality of optical pulses in the receiver device (received by the modulator 201);
determining a decoder initial bit sequence from the plurality of optical pulses ([0037], “Once frame synchronization is established, the base matching process S1102 and S2102 then proceed, with the processor 107 and processor 207 exchanging base matching data and matching results top perform base matching (see Figure 12). If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits”), the determining comprising for each optical pulse at least one of:
determining an approximate intensity profile of the optical pulse by measuring a plurality of intensity values of the optical pulse for a plurality of time bins, and determining, from the approximate intensity profile, a first decoder value of at least one first bit of the decoder initial bit sequence (note: in the Specification, para [0187], Applicant states “The use of the term “at least one” followed by a list of one or more items (for example, “at least one of A and B”) is to be construed to mean one item selected from the listed items (A or B) or any combination of two or more of the listed items (A and B), unless otherwise indicated herein or clearly contradicted by context”; Tanaka et al discloses a phase modulator 201 for determining phase profile; since “at least one of determining an approximate intensity profile … and determining an approximate phase profile” is construed to mean one item selected from the listed items (determining an approximate intensity profile or determining an approximate phase profile), Tanaka et al reads on applicant’s claim limitations even only a phase modulation is present), and
determining an approximate phase profile of the optical pulse by measuring a plurality of phase values of the optical pulse for a plurality of time bins ([0029], “Bob 20 includes a phase modulator 201 that again applies a phase difference to the twin photon pulse sent from Alice 10 through the optical transmission path 30, a Mach-Zehnder interferometer 202 that combines the twin photon pulses, a temperature controller 203 (here a thermoelectric cooler TEC) for adjusting the delay amount of the Mach-Zehnder interferometer 202, two gate-mode photon detectors204 and 205 that are optically connected to the two output ports port1 and port2 of the Mach-Zehnder interferometer 202, respectively, and a random number source 206 that supplies random numbers to the mobile modulator 201”; [0032], “The phase modulator 201 of Bob 20 modulates the optical phase of one of the arriving double optical pulses. In this case, phase modulation is performed randomly so that the relative phase difference (φB) of the two optical pulses is 0 or π/2.These two optical pulses are combined by passing through the Mach-Zehnder interferometer 202, and photon detectors 204 and 205 connected to port 1 and port 2, respectively, detect the interference results according to the modulation phases applied to Alice 10 and Bob 20, respectively”; [0037], “If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits; however, if the bases are different, Bob20 will obtain random values for the detected bits”; Figure 12) and determining, from approximate phase profile, a second decoder value (e.g., the each pulse has a different encode value, e.g., “1” or “0”; [0011]-[0012], “in a quantum cryptographic key distribution method that codes four states using the phase difference between two coherent pulses, a coding set (hereinafter referred to as "X basis") is defined as a pair where phase 0 represents cryptographic key "0" and phase π represents cryptographic key "1".) and a coding set (hereinafter referred to as the "Y basis") in which phase π/2 represents encryption key "0" and phase 3π/2 represents encryption key "1". ) and are selected as two sets of bases using random numbers 2. In other words, for each photon, four different modulations - 0, π/2, π, and 3π/2 - are randomly applied and then transmitted to Bob1013”) of at least one second bit of the decoder initial bit sequence ([0006], “The two-pulse transmission train 1003 is transmitted to the Bob side through the optical transmission path. In the most representative quantum cryptography key distribution algorithm, known as the BB84 protocol (described later), φA takes on four values: 0, π/2, π, and 3π/2, and these four values are randomly assigned to each pulse pair”; [0011], “for each photon, four different modulations—0, π/2, π, and 3π/2—are randomly applied and then transmitted to Bob1013”. The two second bits of the encoder initial bit sequence are the second pair of bits from the asymmetric optical interferometer 102; [0027], “an asymmetric optical interferometer 102 that outputs a double pulse by time-separating the photon pulses”. Figures 11-13 etc.); and
determining, in the transmitter device from the encoder initial bit sequence and in the receiver device from the decoder initial bit sequence, by classical post-processing (107 and 207) and at least one of transmitting classical information (generated from random number source 106 and modulated by modulator 104) from the transmitter device to the receiver device ([0037], “Once frame synchronization is established, the base matching process S1102 and S2102 then proceed, with the processor 107 and processor 207 exchanging base matching data and matching results to perform base matching (see Figure 12). If the modulation bases applied by Alice10 and Bob20 are the same, Bob20 can correctly detect the transmitted bits; however, if the bases are different, Bob20 will obtain random values for the detected bits”. And by the key generation process, [0028], [0030] and [0033]), a shared key shared between the transmitter device and the receiver device ([0038], “the final encryption key is shared between Alice10 and Bob20”. And, [0002]-[0011], [0023]-[0024] and [0103], quantum key distribution QKD; and [0033]).
But, Tanaka et al does not expressly disclose: transmitting further classical information from the receiver device to the transmitter device.
However, to exchange classical information between two processing device is known in the art. E.g., Lesovik et al discloses a system/method to for quantum key distribution includes determining an intrinsic loss along a quantum channel (Figures 1-2, 4 and 8 etc.), and Lesovik et al discloses “The first data processing device and the second data processing device may exchange classical signals via the public channel. Classical signals may also be exchanged via the quantum channel. The optical fiber may be shared by the quantum channel and the classical channel. Alternatively, the quantum channel and the classical channel may be separate” ([0025]), and “The first data processing device 10 and the second data processing device 11 can further exchange classical signals, in particular via a public channel 14. Classical signals may also be exchanged via the quantum channel 13. The optical fibre may be shared by the quantum channel 13 and the classical channel. Alternatively, the quantum channel and the classical channel can be physically separate” ([0072]).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Lesovik et al to the system/method of Tanaka et al so that the two data processing device can exchange classical information, and the functions of the system/method are enhanced.
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Tanaka et al and Lesovik et al as applied to claim 1 above, and further in view of Karpinjski et al: "Control and Measurement of Quantum Light Pulses for Quantum Information Science and Technology," Advanced Quantum Technologies, 2021, 4(9): pages 2000150(23 pp)).
Tanaka et al and Lesovik et al discloses all of the subject matter as applied to claim 1 above. But, Tanaka et al and Lesovik et al do not expressly disclose wherein the intensity function comprises, depending on the first encoder value, an oscillatory component with time-dependent frequency; and/or wherein the phase function comprises, depending on the second encoder value, a further oscillatory component with time-dependent frequency.
However, in quantum communication, to modulate a pulse with a time-dependent frequency is known. E.g., Karpinjski et al discloses a system/method for quantum communications, which can be used for QKD (page “14 of 23”, Figure 9 and right column), and “The temporal-spectral degree of freedom enables multidimensional encoding and processing of quantum information by discretizing the continuous time–frequency state space into time or frequency “bins,” or spectral-temporal pulsed modes” and “The spectral-temporal degree of freedom is also naturally useful for quantum metrology of time and frequency”, and “This is accomplished with the application of time- and frequency-dependent phases” (page “2 of 23”); and “Figure 2 shows the amplitude and phase of a Gaussian pulse with quadratic spectral phase, which introduces correlations between the frequency and arrival time known as “chirp.” The temporal duration 𝜎t of a pulse with flat phase is linked to the spectral bandwidth 𝜎𝜔 by the uncertainty relation 𝜎t ⋅ 𝜎𝜔 ≥ 1∕2, which is saturated only in the case of Gaussian pulses.” That is, Karpinjski et al discloses that a time-dependent frequency is applied to a pulse, and a frequency chirp is generated in the pulse (also refer Figure 4 and pages “9 of 23” – “10 of 23”).
With the frequency chirping, the information capacity can be increased, and security can be improved. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the frequency chirping as taught by Karpinjski et al to the system/method of Tanaka et al and Lesovik et al so to enhance the security and information capacity.
Claims 5-6 are rejected under 35 U.S.C. 103 as being unpatentable over Tanaka et al and Lesovik et al as applied to claim 1 above, and further in view of Yoshino (US 2023/0254045) and Karpinjski et al: "Control and Measurement of Quantum Light Pulses for Quantum Information Science and Technology," Advanced Quantum Technologies, 2021, 4(9): pages 2000150(23 pp)).
1). With regard to claim 5, Tanaka et al and Lesovik et al discloses all of the subject matter as applied to claim 1 above. But, Tanaka et al and Lesovik et al do not expressly disclose wherein the intensity function comprises, depending on the first encoder value, a frequency chirp component.
Regarding modulating an intensity profile of the optical pulse as well as the intensity function, first, Tanaka et al uses a phase modulator (104) not an intensity modulator; however, in QKD, to modulate the intensity of a pulse is well known in the art; and Lesovik et al also discloses that intensity modulator is used for signal modulation ([0113], intensity modulator 41). Second, another prior art, Yoshino discloses a QKD system/method, in which intensity and/or phase of a pulse is modulated depending on encoder values ([0069]-[0072], “the processor 200 performs intensity-modulation (S/V/D) through the intensity modulator 102 and send-data modulation (Y0/Y1/Z0/Z1) through the intensity-phase modulator 104 according to a quantum cipher key (random number) to distribute the quantum cipher key (random number) (Operation S602). According to the present exemplary embodiment, the modulation timing adjustment can be made by the ALICE 100 alone (Operation S601).”).
Regarding the frequency chirp, however, in quantum communication, to modulate a pulse with a time-dependent frequency is known. E.g., Karpinjski et al discloses a system/method for quantum communications, which can be used for QKD (page “14 of 23”, Figure 9 and right column), and “The temporal-spectral degree of freedom enables multidimensional encoding and processing of quantum information by discretizing the continuous time–frequency state space into time or frequency “bins,” or spectral-temporal pulsed modes” and “The spectral-temporal degree of freedom is also naturally useful for quantum metrology of time and frequency”, and “This is accomplished with the application of time- and frequency-dependent phases” (page “2 of 23”); and “Figure 2 shows the amplitude and phase of a Gaussian pulse with quadratic spectral phase, which introduces correlations between the frequency and arrival time known as “chirp.” The temporal duration 𝜎t of a pulse with flat phase is linked to the spectral bandwidth 𝜎𝜔 by the uncertainty relation 𝜎t ⋅ 𝜎𝜔 ≥ 1∕2, which is saturated only in the case of Gaussian pulses.” That is, Karpinjski et al discloses that a time-dependent frequency is applied to a pulse, and a frequency chirp is generated in the pulse (also refer Figure 4 and pages “9 of 23” – “10 of 23”. Also, refer to Figures 4-5 and 9-10; and in optics, the instantaneous frequency of a wave is the time derivative of its phase; or a change of phase with time directly gives the frequency).
With the frequency chirping, the information capacity can be increased, and security can be improved. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the intensity modulation and frequency chirping as taught by Yoshino and Karpinjski et al to the system/method of Tanaka et al and Lesovik et al so that both intensity and phase can be used for coding, and further frequency chirping is applied to the pulse, and then the security and information capacity are improved.
2). With regard to claim 6, Tanaka et al and Lesovik et al and Yoshino and Karpinjski et al disclose all of the subject matter as applied to claims 1 and 5 above. And the combination of Tanaka et al and Lesovik et al and Yoshino and Karpinjski et al further discloses wherein the frequency chirp component includes at least one of a linear frequency chirp component, a quadratic frequency chirp component, a cubic frequency chirp component, and an exponential frequency chirp component (Karpinjski: pages “9 of 23” to “10 of 23”. Figures 4-5 and 9-10; “By calculating the temporal derivative of the phase of the above expression one can easily find that the instantaneous frequency is linearly chirped at a rate K, being given by 𝜔0 + K(t − t0).”).
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Tanaka et al and Lesovik et al as applied to claim 1 above, and in further view of Shen et al (US 2024/0187207).
Tanaka et al and Lesovik et al disclose all of the subject matter as applied to claim 1 above. But, Tanaka et al and Lesovik et al do not expressly disclose wherein each optical pulse has a pulse length from 1 ns to 1000 ns.
However, Shen et al discloses a quantum cryptography system and a receiver for a quantum cryptography, and discloses that the power of an optical pulse depends on the pulse length ([0046], “For example, at 1000 nm wavelength and 100 ns pulse length, the average optical pulse power absorbed by the detector on the order of tens of pW should be sufficient to create a photon detection event with high probability. As another example, for 1000 nm wavelength and a 1 ns pulse length, a pulse power on the order of nW should be sufficient to create a photon detection event with high probability).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to apply the teachings of Shen et al to the system/method of Tanaka et al and Lesovik et al so that both intensity and phase can be used for coding, and further frequency chirping is applied to the pulse, and then the security and information capacity are improved.
Claim 11 is rejected under 35 U.S.C. 103 as being unpatentable over Tanaka et al and Lesovik et al as applied to claim 9 above, and in further view of Meyers et al (US 2012/0327287).
Tanaka et al and Lesovik et al disclose all of the subject matter as applied to claim 9 above. But, Tanaka et al and Lesovik et al do not expressly disclose the method according to claim 9, further comprising at least one of: determining a first measured correlator difference from the approximate intensity profile and the ideal approximate intensity profiles and determining the first decoder value by comparing the first measured correlator difference with a first threshold value; and determining a second measured correlator difference from the approximate phase profile and the ideal approximate phase profiles and determining the second decoder value by comparing the second measured correlator difference with a second threshold value (also refer to 112 rejection above).
However, first, Tanaka et al discloses “By obtaining an output of 0 or 1 based on this difference in modulation phase depth, and then comparing a portion of the conditions under which the output data was measured between Alice and Bob, it is ultimately possible to share the same bit sequence between Alice and Bob” ([0004]), “determines the detection signal S0 from the balanced photodetector 806 by comparing itwith the threshold levels. As will be described later, it divides the signal into a confirmed determination signal and a provisional determination signal and outputs them to the processor 801.Similarly, the multi-level discrimination circuit 809 maintains three threshold levels L0, L1, and L2, and determines the detection signal S1 from the balanced photodetector 807 by comparing it with the threshold levels” ([0067]), “adjusts the delay amount of the interference means based on a comparison of the error rate with a predetermined reference value” ([0082] and [0089] [0095]). That is, Tanaka et al discloses a scheme to compare a detected signal with a threshold.
Second, Meyers et al discloses a quantum communication system/method, and “A correlation and phase difference calculation element 16 correlates the detection signals from detectors 14 and 15 to derive the three dimensional target information” ([0089]-[0091]), that is, correlator difference from a phase is calculated. Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to combine Meyers et al with Tanaka et al and Lesovik et al so to determine the second measured correlator difference from the approximate phase profile and an ideal approximate phase profiles, and to compare the second measured correlator difference with a second threshold value so to accurately and properly determine the second decoder value.
Conclusion
The prior art made of record and not relied upon is considered pertinent to applicant's disclosure.
US 20100080394 A1
US 7555127 B2
US 20080037998 A1
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/LI LIU/Primary Examiner, Art Unit 2634
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