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 .
Claim Rejections - 35 USC § 112 - Indefinite
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.
Claims 1-6 are 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 1 , line 5 recites “a first modulation branch”. There is insufficient antecedent basis for this limitation.
Claim 3 , recites “a first sideband suppressing optical circuit”. There is insufficient antecedent basis for this limitation.
Claim 5 , recites “a first sideband suppressing optical circuit”. There is insufficient antecedent basis for this limitation.
Claims 2-6 are also rejected because they depend from one or more of the claims rejected above and they fail to further limit the scope in a manner to overcome the rejection.
Claim Rejections - 35 USC § 103 - Obvious
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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.
This application currently names joint inventors. In considering patentability of the claims the examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
Claim(s) 1, 3, and 5 is/are rejected under 35 U.S.C. 103 as being unpatentable over US 8,879,873 (Goh) in view of US 2010/0054757 (Smith).
Regrading claim 1, Goh teaches a single sideband signal generator, comprising:
a modulator configured to generate a first and a second modulated optical signals which have equal amplitudes but opposite phases (FIG. 1A: modulator generating first and second modulated optical signals at outputs of modulators/modulation branches 9, 10); and
a sideband suppressing optical circuit including:
a first optical delay line path coupled to the first modulation branch and configured to obtain a first photonic RF phase-shifted optical signal based on the first modulated optical signal (FIG. 1A: phase delay line path 11 coupled to modulation branch 10);
a first optical bypass line path coupled to second modulation branch and configured to obtain a first bypass optical signal based on the second modulated optical signal (FIG. 1A: line path between modulation branch 9 and optical combiner 7f bypasses the delay line path 11);
and a first optical combiner coupled to the first optical delay line path and the first optical bypass line path and configured to combine the first photonic RF phase-shifted optical signal and the first bypass optical signal to obtain a first full-carrier single sideband signal (FIG. 1A: combiner 7f).
FIG. 1A is reproduced for reference.
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The delay line 11 is a 90 degree optical phase shifter. See the bottom of col. 2:
(8) In the nest MZI modulator, as shown in FIGS. 1A and 1B, the CW lights branched by a 3 dB coupler 7a are respectively binary phase-modulated by the child MZI modulators (an MZI modulator for Ich 9 and an MZI modulator for Qch 10) (see D and E in FIG. 1B) and take a 90.degree. phase shift with a .pi./2 optical phase shifter 11 (see F in FIG. 1B), and those modulation signals are combined by a 3 dB coupler 7f to give a quaternary phase-modulated QPSK signal light as shown in G of FIG. 1B. Note that, the .pi./2 optical phase shifter is actually realized by the adjustment with a subsequent phase adjuster (variable optical phase shifter) 12, and the .pi./2 optical phase shifter is often omitted without being individually provided.
In other words, the phase shifter 11 is an optical delay line path.
Furthermore, it was known that Mach-Zehnder interferometers can be modulated at RF frequencies. See, for example, Smith at:
[0003] Exemplary embodiments of the present invention will be described hereafter with particular reference to a bias controller for a Mach-Zehnder modulator (often known simply as an MZ modulator), the controller and modulator being employed in a communications system to modulate an input optical carrier signal with a radio frequency (RF) communications signal. Whilst the teachings of the present invention have great utility in optical communications systems, that is to say communications systems where the nodes of the system are optically connected, it will be immediately appreciated by persons of ordinary skill in the art that the teachings of the invention may otherwise be applied. Accordingly, the following illustrative description should not be read as being limited solely to communications systems or indeed to MZ modulators.
It would have been obvious that the optical signals in Gao be implemented in a known manner, such as RF optical signals as taught in Smith. In particular, Gao and Smith are in the same technical field (e.g., optical communications) and the results would have been predictable.
Regarding claim 3, Goh teaches the single sideband signal generator according to claim 1, wherein the first sideband suppressing optical circuit further comprises an adjustable phase shifter coupled to the first optical delay line path, and configured for fine-tuning the first photonic RF phase-shifted optical signal (FIG. 1A: adjustable phase shifter 12b).
See also Goh at the bottom of col. 2:
(8) In the nest MZI modulator, as shown in FIGS. 1A and 1B, the CW lights branched by a 3 dB coupler 7a are respectively binary phase-modulated by the child MZI modulators (an MZI modulator for Ich 9 and an MZI modulator for Qch 10) (see D and E in FIG. 1B) and take a 90.degree. phase shift with a .pi./2 optical phase shifter 11 (see F in FIG. 1B), and those modulation signals are combined by a 3 dB coupler 7f to give a quaternary phase-modulated QPSK signal light as shown in G of FIG. 1B. Note that, the .pi./2 optical phase shifter is actually realized by the adjustment with a subsequent phase adjuster (variable optical phase shifter) 12, and the .pi./2 optical phase shifter is often omitted without being individually provided.
In other words, the phase shifters 12 are variable phase shifters.
Regarding claim 5, Goh teaches the single sideband signal generator according to claim 1, wherein the first sideband suppressing optical circuit further comprises an adjustable phase shifter coupled to the first bypass line path, and configured for fine-tuning the first bypass optical signal (FIG. 1A: adjustable phase shifter 12a).
See also the discussion of claim 3.
Claim(s) 2 is/are rejected under 35 U.S.C. 103 as being unpatentable over the art as applied to claim 2 above, and further in view of US 2022/0260779 (Yang).
Regarding claim 2, Yang teaches the single sideband signal generator according to claim 1, wherein the first optical delay line path is based on a thin film waveguide made of any one of: silicon, lithium niobate, lithium tantalate, gallium arsenide, indium phosphide, barium titanate, and aluminium gallium arsenide.
Yang teaches that it was known to make a modulator including lithium niobate thin film waveguide. See:
[0005] Optionally, the lithium niobate thin film modulator includes: a first substrate; a first buried silica layer arranged on the first substrate; a first lithium niobate thin film waveguide arranged on the first buried silica layer according to a first preset shape; a metal electrode arranged on both sides of the first lithium niobate thin film waveguide layer; a first cladding silica layer covering the first buried silica layer, the first lithium niobate thin film waveguide and the metal electrode, wherein the first cladding silica layer is provided with a through hole to expose the metal electrode; a terminal resistor connected to the metal electrode through the through hole; a metal lead wire connected to the metal electrode through the through hole; and a first top silica layer covering the first cladding silica layer and the terminal resistor.
It would have been obvious that Gao can be implemented in a known manner, such as with the modulator based on a thin film waveguide made of lithium niobate as taught in Yang. In particular both are in the same technical field (e.g., optical communications) and the results would have been predictable.
Claim(s) 4 is/are rejected under 35 U.S.C. 103 as being unpatentable over the art as applied to claim 3 above, and further in view of US 2006/0127104 (Harley).
Regarding claim 4, Harley teaches the single sideband signal generator according to claim 3, wherein the adjustable phase shifter is a thermo-optic phase shifter, an electro-optic phase shifter, a MEMS phase shifter, or a free-carrier depletion phase shifter.
Harley teaches that it was known for variable phase shifters to be electro-optic. See:
[0045] As mentioned above, the drive signals S.sub.x(t) are formatted to drive phase and amplitude excursions of the output optical signal E.sub.O(t). As is known in the art, each branch 28x of an MZ interferometer comprises an electro-optic variable phase shifter. ...
It would have been obvious that Gao can be implemented in a known manner, such as with the phase shifters of a known type, such as those taught in Harley. In particular both are in the same technical field (e.g., optical communications) and the results would have been predictable.
Claim(s) 6 is/are rejected under 35 U.S.C. 103 as being unpatentable over the art as applied to claim 5 above, and further in view of US 2006/0127104 (Harley).
Regarding claim 6, Harley teaches the single sideband signal generator according to claim 5, wherein the adjustable phase shifter is a thermo-optic phase shifter, an electro-optic phase shifter, a MEMS phase shifter, or a free-carrier depletion phase shifter.
Harley teaches that it was known for variable phase shifters to be electro-optic. See:
[0045] As mentioned above, the drive signals S.sub.x(t) are formatted to drive phase and amplitude excursions of the output optical signal E.sub.O(t). As is known in the art, each branch 28x of an MZ interferometer comprises an electro-optic variable phase shifter. ...
It would have been obvious that Gao can be implemented in a known manner, such as with the phase shifters of a known type, such as those taught in Harley. In particular both are in the same technical field (e.g., optical communications) and the results would have been predictable.
Allowable Subject Matter
Claims 7-20 are allowed.
The following is an examiner’s statement of reasons for allowance. The prior art of record teaches the general subject matter of the claims (see the rejections above) but does not appear to teach the particular embodiments in claims 7-20.
US 8,879,873 (Goh) is the closest art of record (see the discussion of Goh in the rejections above). FIG. 4A illustrates a device with first and second modulation branches 1a, 1b, each with a delay line 11a, 11b in one arm of each modulation branch, and each with a bypass path in the other arm of each modulation branch. There are also variable phase shifters 12 in each arm of each modulation branch.
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However, it does not teach the particular connection to the first and second modulated signals from the modulator as recited in the claims.
US 6,118,566 (Price) at FIG. 11 illustrates a transmitter including an optical source 34, electrical carrier source 42, an amplifier 54, a modulator 44, and a controller 20 controlling elements of the transmitter including the amp 54 and modulator 44.
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See also col. 8, 3rd paragraph:
(19) In the transmitter 12 of FIG. 11, the electrical baseband signal .LAMBDA..sub.B can be encoded along with a clock signal .LAMBDA..sub.CLK using a data encoder 50 to provide an encoded data signal .LAMBDA..sub.C. The encoded data signal .LAMBDA..sub.C may be further passed through a filter 52, such as a low pass filter, to shape the signal before being passed to the signal distorter 32. In the transmitter 12 of FIG. 11, the IQ modulator 46 can be used to modulate the distorted electrical signal onto the electrical carrier frequency .nu..sub.e. The electrical carrier can be amplified using an electrical amplifier 54, split through electrical coupler 56, and upconverted onto the optical carrier to produce the distorted optical signal .LAMBDA..sub.OD having its center wavelength at .lambda..sub.o.+-.e. One of the controllers 20 in the system 10 can be used to provide feedback control of the upconverter 44, as well as the other components such as the amplifier 54.
See also, col 5, 5th full paragraph:
(7) The feedback controller 20 may be, for example, a processor, such as a general purpose processor or an application specific integrated circuit. The feedback controller 20 receives feedback from one or both of the transmitter 12 and receiver 14, or from other elements of the system 10, and makes adjustments to the system 10 in response to that feedback.
See also the paragraph spanning cols 5-6:
One or more signal lasers … can be used as the optical source 34.
Price at FIG. 14 shows the modulator in more detail including the modulating electrodes 64.
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The electrical signals/voltage on the input and/or bias electrodes will modulate the optical carrier. See, for example, col. 9, third full paragraph:
… Electrical input signals v.sub.1 and v.sub.2 are provided to the upconverter respective input electrodes 64.sub.1 and 64.sub.2 via first and second inputs, 68.sub.1 and 68.sub.2, respectively. The input signals v.sub.1 and v.sub.2 are upconverted onto the respective split lightwaves passing between the electrodes and combined in cascaded optical combiners 70 to produce the upconverted optical signal .LAMBDA..sub.o.
FIGS. 1a-1c illustrate different ways that were known to modulation the intensity of the optical carrier. See also col. 2, first paragraph:
Data streams can be modulated onto the lightwave using a number of different schemes. The two most common schemes are return to zero (RZ) and non-return to zero (NRZ). In RZ modulation, the modulation of each bit of information begins and ends at the same modulation level, i.e., zero, as shown in FIG. 1(a). In NRZ schemes, the modulation level is not returned to a base modulation level, i.e., zero, at the end of a bit, but is directly adjusted to a level necessary to modulate the next information bit as shown in FIG. 1(b). Other modulation schemes, such as duobinary and PSK, encode the data in a waveform, such as in FIG. 1(c), prior to modulation onto a carrier.
Col. 4, first full paragraph, discusses the electrical signal being used to modulate, or upconvert data onto, the optical carrier:
In an embodiment, an information data stream is modulated on to an electrical carrier, such radio frequency ("RF") or microwave carrier, frequency .nu..sub.e. The modulated electrical carrier is upconverted on to a lightwave carrier having a wavelength .lambda..sub.0 and frequency .nu..sub.o produced by the optical transmission source to produce an information carrying lightwave at wavelength .lambda..sub.1 and frequency .nu..sub.o.+-.e. The upconverter can be used to simultaneously upconvert a plurality of electrical frequencies onto different subcarrier lightwaves. In an embodiment, the information is modulated onto the electrical carrier in duobinary format, which provides for more narrow subcarrier bandwidths.
Price also teaches the use of bias electrodes in the modulator. See col. 9, last full paragraph.
In an embodiment, LiNbO.sub.3 is used to form the optical paths 62.sub.i' and 62.sub.i", which can be used to produce linearly polarized optical signals. In addition, bias electrodes can be provided in optical paths 62.sub.i' and 62.sub.i" and/or 62.sub.i after passing through the input electrodes 64.sub.1 and 64.sub.2. The bias electrodes can be used to trim the phase difference of the optical signals upconverted onto the subcarrier lightwaves in each path before the signals are combined.
In other words, bias electrodes were known for use in trimming the phase difference in the optical signals in the legs of the modulator.
FIGS. 1a-1c illustrate different ways that were known to modulation the intensity of the optical carrier. See also col. 2, first paragraph:
Data streams can be modulated onto the lightwave using a number of different schemes. The two most common schemes are return to zero (RZ) and non-return to zero (NRZ). In RZ modulation, the modulation of each bit of information begins and ends at the same modulation level, i.e., zero, as shown in FIG. 1(a). In NRZ schemes, the modulation level is not returned to a base modulation level, i.e., zero, at the end of a bit, but is directly adjusted to a level necessary to modulate the next information bit as shown in FIG. 1(b). Other modulation schemes, such as duobinary and PSK, encode the data in a waveform, such as in FIG. 1(c), prior to modulation onto a carrier.
US 5,101,450 (Olshansky) at FIG. 18 teaches a MZM with modulating electrodes 274, 278, 290, 294, and bias electrodes 308, 310.
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See also, for example, col. 16, first paragraph after Eqn 24:
(69) where .phi..sub.1 =.pi.v.sub.1 (t)/v.sub..pi., and .phi..sub.2 =.pi.v.sub.2 (t)/v.sub..pi.. The modulation signals applied to electrodes 274, 278, 290 and 294 can be generated by electrical transmitters of the type shown in FIG. 4 and described hereinabove, with appropriate signal inversion and addition of DC bias voltages. An adjustable DC voltage can be applied between electrodes 308 and 310 to insure phase quadrature between the output signals from modulators 270 and 272.
It also teaches that electrical signals on carriers at RF or microwave frequency can be used to modulate the optical signal. See, for example, the paragraph spanning cols. 1-2:
Subcarrier multiplexed (SCM) optical communication systems have also been proposed as a means for providing increased transmission bandwidth. A wideband signal composed of many frequency multiplexed carriers at either RF or microwave frequencies is used to modulate an optical carrier. The optical signal is transmitted through a conventional single mode optical fiber to a remote location. The optical signal received at the remote location is detected with a high speed photodiode, and the transmitted signals are recovered with a conventional RF or microwave receiver. The RF or microwave carriers can be modulated by either analog or digital signals and can be used to carry voice, data, video, digital audio and high definition video, in almost any combination of services.
The optical carrier can be generated by a laser, as shown in FIG. 3 and discussed at col. 3, last paragraph to col. 4, first full paragraph:
A block diagram of an optical transmitter wherein second order IMP's are cancelled is shown in FIG. 3. By cancelling second order IMP's, closer spacing between optical carriers can be utilized as described hereinafter. A first laser 40 directs an optical carrier at a first frequency f.sub.1 to an intermod-cancelling (IC) optical phase modulator 42. A second laser 44 directs an optical carrier at a second optical frequency f.sub.2 to an IC optical phase modulator 46. An Nth laser 48 directs an optical carrier at an Nth optical frequency f.sub.N to an IC optical phase modulator 50. The number N of lasers and IC modulators in the system depends on the number of modulated optical carriers to be transmitted. The outputs of modulators 42, 46-50 are connected to an optical fiber 52 for transmission of a composite optical signal to one or more remote locations. An electrical transmitter 54 provides a modulation signal to modulator 42; an electrical transmitter 56 provides a modulation signal to modulator 46; and an electrical transmitter 58 provides a modulation signal to modulator 50.
The lasers 40, 44-48 can, for example, be distributed feedback semiconductor lasers as described by H. Soda et al in "Stability in Single Longitudinal Mode Operation in GaInAsP/InP Phase-Adjusted DFB Lasers", IEEE J. Quantum Electronics, Vol. QE-23, June 1987, pages 804-814. A laser control 60 provides to the lasers 40, 44-48 signals which control the optical frequencies of each laser so as to permit close optical carrier frequency spacing.
US 2007/0212075 (Yin) at FIG. 3 teaches a dual parallel Mach-Zehnder Modulator (MZM) 300 with modulator bias control, including bias electrodes 302, 304 for each MZM, and one bias electrode 305for the output of the lower MZM.
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FIG. 5 illustrates using a filter 502 in a feedback loop to control a bias controller 508.
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FIG. 7 illustrates an embodiment for DQPSK operations.
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FIG. 8 illustrates a variation for SSB operations.
FIG. 13 illustrates a bias controller with tuning capability using a pilot tone.
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See, for example:
[0037] In some applications, it may be desirable to lock to points other than the Null, Peak, Quad+ and Quad- points. FIG. 13 shows a block diagram of a bias controller with tuning capability (1300). The bias controller generates a pilot tone to apply to the system. A photo detector (1308) senses the optical signal that split from the optical coupler (or splitter), which contains the pilot tone signal. A filter (1310) filters out the desired harmonics of the pilot tone signal, and a synchronous detector (1304) provides the amplitude of these harmonics, which form an error signal. An extra error signal (1302) is applied here with an amplitude that can be set by a user of the system. With a Proportional Integrator (1306), the feedback loop is closed, the error is eliminated, and the DC bias, which is needed to eliminate the error, is provided to the system.
US 2014/0010533 (Yan) at FIG. 1 teaches a dual parallel Mach Zehnder Modulator (DP-MZM) using a bias controller for monitoring the output optical power of an I/Q modulator, adjusting the DC Bias voltages of the I, Q, and Phase modulators (see the Abstract). FIG. 6 illustrates one embodiment.
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Other embodiments are illustrated in FIGS. 7-15.
In particular, it calculates bias voltage indicating values of the I modulator, the Q modulator, and the phase modulator according to the optical output power and known modulation data, with particular emphasis on evenness of distribution of power of output optical signals in the four quadrants of the I/Q plane. See, for example, the discussion beginning at [0054].
Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.”
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to DARREN WOLF whose telephone number is (571)270-3378. The examiner can normally be reached Monday through Friday, 7:00 AM to 3:00 PM.
Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice.
If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, KENNETH N. VANDERPUYE can be reached at 571-272-3078. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/DARREN E WOLF/Primary Examiner, Art Unit 2634
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