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
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 4, 12, and 16 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.
Claims 4, 12, and 16 recite “a time for the reference signal to travel the optical pathway from the splitter to the light signal combiner is greater than or equal to 50% and less than or equal to 100% of a time for light in the misdirected signal to travel from the splitter, to the misdirection source, and to the light signal combiner.”
However, Paragraph [0006] of Applicant Specification states “The LIDAR system is constructed such that the time for the reference signal to travel from the splitter to the light signal combiner is greater than or equal to 30% and less than or equal to 100% of the time for the light included in the misdirected signal to travel from the splitter, to the misdirection source, and to the light signal combiner. Furthermore, Paragraph [0089] states “Additionally or alternately, in some instances, the time for the reference signal to travel from the splitter the light signal combiner (td) is more than 30%, 60%, or 70% and less than 80%, 90%, or 100% of the time for an outgoing LIDAR signal to travel from the splitter”
The applicant has not provided sufficient guidance to show that a person of ordinary skill in the art would understand the inventor possessed the specific 50% lower limit. Therefore, a range of 50% to 100% represents an arbitrary selection not described by the inventor. For these reasons, Claims 4, 12, and 16 fail to satisfy the written description requirement.
Claim Rejections - 35 USC § 103
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.
Claims 1-2, 5-7, 9-10, and 13-15 are rejected under 35 U.S.C. 103 as being unpatentable over Koonath et al. (US 2022/0113390) in view of Forsman et al (US 2003/00183603).
Regarding Claim 1, Koonath teaches a system ([Abstract] A LIDAR system), comprising:
a LIDAR system that includes a signal splitter configured to receive an outgoing LIDAR signal ([0025] The splitter 22 moves a portion of the light source signal from the utility waveguide 12 onto a reference waveguide 24 as a first reference signal . The reference waveguide 24 carries the first reference signal to the processing unit 20 for further processing),
the LIDAR system being configured to transmit a system output signal from the LIDAR system, the system output signal including light from the outgoing LIDAR signal received by the splitter ([0022] The utility waveguide 12 terminates at a facet 14 and carries the outgoing LIDAR signal to the facet 14. The facet 14 can be positioned such that the outgoing LIDAR signal traveling through the facet 14 exits the LIDAR chip and serves as a LIDAR output signal);
the LIDAR system including a light signal combiner configured to combine light that returns to the LIDAR system from the system output signal with light from a reference signal so as to generate a composite signal beating at a composite beat frequency ([0024] Light from the system return signal can be carried in a first LIDAR input signal that is received by the LIDAR chip. In some instances, a portion of the system return signal can serve as the first LIDAR input signal. The first LIDAR input signals enters a comparative waveguide 16 through the facet 18 and serves as a first comparative signal [0032] As will be described in more detail below, the first processing unit 20 and the second processing unit 40 each combines a comparative signal with a reference signal to form a composite signal that carries LIDAR data for a sample region on the field of view [0068] Due to the difference in frequencies between the comparative signal contribution and the reference signal contribution, the composite signal is beating between the comparative signal contribution and the reference signal contribution),
the reference signal including light from the outgoing LIDAR signal received by the splitter ([0025] The splitter 22 moves a portion of the light source signal from the utility waveguide 12 onto a reference waveguide 24 as a first reference signal . The reference waveguide 24 carries the first reference signal to the processing unit 20 for further processing).
Koonath is not relied upon as teaching that a length of an optical pathway from the splitter to the light signal combiner being greater than 1 picosecond and less than 1 nanosecond.
However, Forsman teaches that a length of an optical pathway from the splitter to the light signal combiner being greater than 1 picosecond and less than 1 nanosecond ([0053] the system of FIG. 3A illustrates a simple structure to produce a burst comprising 2 pulses having the appropriate pulse durations and time in between pulses. It is understood that the duration between pulses may be easily modified by altering the distance of the beam splitter 304/beam combiner 306 and the reflecting mirrors 310 and 312, i.e., changing the length of the path traversed by the second pulse [Abstract] wherein each burst comprises at least two laser pulses, wherein each laser pulse has a pulse duration within a range of between approximately 10 ps and 100 ns).
Koonath and Forsman are considered to be analogous to the claimed invention because they are both in the same field of LIDAR and optical sensing systems. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have modified the optical path configuration of Koonath to include the specific pulse-timing and path-length parameters disclosed by Forsman with a reasonable expectation of success. This modification would have been motivated by the desire to improve the timing precision and signal-processing reliability of the LIDAR system. By integrating Forsman’s teaching of specific path-length ranges into Koonath’s LIDAR architecture, the system can better synchronize reference signals with return signals to enhance composite beat frequency detection. A person of ordinary skill in the art would recognize that utilizing these specific timing ranges would yield the predictable result of improved ranging accuracy and reduced signal ambiguity.
Regarding Claims 2 and 10, Koonath teaches that the splitter is configured to output a portion of the outgoing LIDAR signal that travels an optical pathway from the splitter to a location where the portion of the outgoing LIDAR signal is transmitted from the LIDAR system as the system output signal ([0022] The utility waveguide 12 terminates at a facet 14 and carries the outgoing LIDAR signal to the facet 14. The facet 14 can be positioned such that the outgoing LIDAR signal traveling through the facet 14 exits the LIDAR chip and serves as a LIDAR output signal), the optical pathway including a misdirection source that reflects a misdirected portion of the first portion of the outgoing LIDAR signal that serves as a misdirected signal, the misdirected signal being received at the light signal combiner ([0082]-[0083] The system peaks occur as a result of misdirected light from the outgoing LIDAR signal being included in the composite signal without traveling the LIDAR path that is designed for the signals to travel through the LIDAR system. The light from the outgoing LIDAR signal that does not travel the LIDAR path can be considered a misdirected signal. In some instances, the misdirected signal does not leave the LIDAR assembly or the LIDAR system. Accordingly, light from the misdirected signal is often not included in the system output signal. As a result, light from the misdirected light is often not reflected by an object located in a sample region. Example sources of a misdirected signal (misdirection sources) include, but are not limited to, reflections, cross talk between optical components in the LIDAR system, and light scattered by component(s) of the LIDAR system).
Regarding Claims 5 and 13, Koonath teaches that the misdirection source is a last one of multiple misdirection sources included in the LIDAR system, each misdirection source reflecting one of multiple misdirected portions of the first portion of the outgoing LIDAR signal that serves as one of multiple misdirected signals, each of the misdirected signals being received at the light signal combiner ([0004] A portion of the light is also included in one or more misdirected signals. Each of the misdirected signals travels a different misdirected path from the light source to the filter. Each of the misdirected paths is a different path from the LIDAR path [0082]-[0083] The system peaks occur as a result of misdirected light from the outgoing LIDAR signal being included in the composite signal without traveling the LIDAR path that is designed for the signals to travel through the LIDAR system. The light from the outgoing LIDAR signal that does not travel the LIDAR path can be considered a misdirected signal. In some instances, the misdirected signal does not leave the LIDAR assembly or the LIDAR system. Accordingly, light from the misdirected signal is often not included in the system output signal. As a result, light from the misdirected light is often not reflected by an object located in a sample region. Example sources of a misdirected signal (misdirection sources) include, but are not limited to, reflections, cross talk between optical components in the LIDAR system, and light scattered by component(s) of the LIDAR system).
Regarding Claims 6 and 14, Koonath teaches that the last misdirection source is the misdirection source where a time for the outgoing LIDAR signal to travel between the misdirection source and the location where the outgoing LIDAR signal is transmitted from the LIDAR system as the system output signal is the shortest ([0087] As is evident from the labels SPA and SPB in FIG. 8B, the misdirection sources are each a feature of the LIDAR path where one of the misdirection signals that is traveling along the LIDAR path is diverted from traveling the full length of the LIDAR path Examiner Note: Fig. 8B, reproduced below, shows SPB as the last misdirection source in terms of flow of light from the illumination unit to the transmission location and also shows that it is physically closest to the transmission location).
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Regarding Claims 7 and 15, Koonath teaches that the splitter is configured to output the reference signal ([0021] The LIDAR chip includes a utility waveguide 12 that receives the light source signal from the light source 10. The utility waveguide 12 includes a splitter 22 that receives the light source signal. The splitter outputs an outgoing LIDAR signal on the utility waveguide 12).
Regarding Claim 9, Koonath teaches a system ([Abstract] A LIDAR system), comprising:
a LIDAR system that includes a signal splitter configured to receive an outgoing LIDAR signal ([0025] The splitter 22 moves a portion of the light source signal from the utility waveguide 12 onto a reference waveguide 24 as a first reference signal . The reference waveguide 24 carries the first reference signal to the processing unit 20 for further processing),
the LIDAR system being configured to transmit a system output signal from the LIDAR system, the system output signal including light from the outgoing LIDAR signal received by the splitter ([0022] The utility waveguide 12 terminates at a facet 14 and carries the outgoing LIDAR signal to the facet 14. The facet 14 can be positioned such that the outgoing LIDAR signal traveling through the facet 14 exits the LIDAR chip and serves as a LIDAR output signal);
the LIDAR system including a light signal combiner configured to combine light that returns to the LIDAR system from the system output signal with light from a reference signal so as to generate a composite signal beating at a composite beat frequency ([0024] Light from the system return signal can be carried in a first LIDAR input signal that is received by the LIDAR chip. In some instances, a portion of the system return signal can serve as the first LIDAR input signal. The first LIDAR input signals enters a comparative waveguide 16 through the facet 18 and serves as a first comparative signal [0032] As will be described in more detail below, the first processing unit 20 and the second processing unit 40 each combines a comparative signal with a reference signal to form a composite signal that carries LIDAR data for a sample region on the field of view [0068] Due to the difference in frequencies between the comparative signal contribution and the reference signal contribution, the composite signal is beating between the comparative signal contribution and the reference signal contribution),
the reference signal including light from the outgoing LIDAR signal received by the splitter ([0025] The splitter 22 moves a portion of the light source signal from the utility waveguide 12 onto a reference waveguide 24 as a first reference signal . The reference waveguide 24 carries the first reference signal to the processing unit 20 for further processing).
Koonath is not relied upon as teaching the LIDAR system being constructed such that a time for the reference signal to travel from the splitter to the light signal combiner being greater than 1 picosecond and less than 1 nanosecond.
However, Forsman teaches the LIDAR system being constructed such that a time for the reference signal to travel from the splitter to the light signal combiner being greater than 1 picosecond and less than 1 nanosecond ([0053] the system of FIG. 3A illustrates a simple structure to produce a burst comprising 2 pulses having the appropriate pulse durations and time in between pulses. It is understood that the duration between pulses may be easily modified by altering the distance of the beam splitter 304/beam combiner 306 and the reflecting mirrors 310 and 312, i.e., changing the length of the path traversed by the second pulse [Abstract] wherein each burst comprises at least two laser pulses, wherein each laser pulse has a pulse duration within a range of between approximately 10 ps and 100 ns).
Koonath and Forsman are considered to be analogous to the claimed invention because they are both in the same field of LIDAR and optical sensing systems. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have modified the reference signal path length of Koonath to include the specific timing parameters of Forsman with a reasonable expectation of success. This modification would have been motivated by the desire to ensure proper signal synchronization and phase stability within the coherent detection architecture. By integrating Forsman’s teaching of specific pathlength delays into Koonath’s LIDAR system, the system can more effectively align reference and return signals at the light signal combiner. A person of ordinary skill in the art would recognize that this specific delay range would yield the predictable result of improved beat frequency generation and overall system ranging precision.
Claims 3 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Koonath et al. (US 2022/0113390) and Forsman et al (US 2003/00183603) in further view of Schrӧder et al. (US 11,768,419 B1).
Regarding Claims 3 and 11, Koonath is not relied upon as teaching that the misdirection source is a surface of the lens.
However, Schrӧder teaches that the misdirection source is a surface of the lens ([Col. 16, ll. 39-48] In addition, as shown in FIG. 8A, using an upstream lens array 520 with a longer focal length (F.sub.U) than that the downstream lens array 640 focal length (F.sub.U), in combination with additional aspects of the example beam steering system 800 (e.g., arranging the multi-segment LC beam steering device 502 upstream of the upstream lens array focal plane (Z=0)), may substantially eliminate the presence of misdirected beams B.sub.M (see FIG. 7A for comparison), and thereby increase a beam steering efficiency provided by the beam steering system).
Koonath (as previously modified by Forsman) and Schrӧder are considered to be analogous to the claimed invention because they are both in the same field of LIDAR and optical sensing systems. Therefore, it would have been obvious to ta person of ordinary skill in the art before the effective filing date of the claimed invention to have modified the LIDAR system of Koonath (as previously modified by Forsman) to include the lens surface misdirection source teachings of Schrӧder with a reasonable expectation of success. This modification would have been motivated by the desire to identify and mitigate noise sources within the optical path of the system. By integrating Schrӧder’s teaching of lens surface reflections as a specific misdirection source into Koonath (as previously modified by Forsman)’s LIDAR architecture, the system can more accurately characterize internal noise components. A person of ordinary skill in the art would recognize that explicitly accounting for lens surface reflections would yield the predictable result of improved signal-to-noise ratio and more reliable beam steering efficiency.
Claims 4 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Koonath et al. (US 2022/0113390) and Forsman et al (US 2003/00183603) in further view of Piggott et al. (US 2022/0187458 A1).
Regarding Claims 4 and 12, Koonath is not relied upon as teaching that a time for the reference signal to travel the optical pathway from the splitter to the light signal combiner is greater than or equal to 50% and less than or equal to 100% of a time for light in the misdirected signal to travel from the splitter, to the misdirection source, and to the light signal combiner.
However, Piggott teaches that a time for the reference signal to travel the optical pathway from the splitter to the light signal combiner is greater than or equal to 50% and less than or equal to 100% of a time for light in the misdirected signal to travel from the splitter, to the misdirection source, and to the light signal combiner ([0085] FIG. 4B is a block diagram illustrating an example implementation of an optical sensing system 403 with frequency multiplexing and efficient detection of targets in the presence of internal reflection… Internal reflections, (close-up returns, back reflections, etc.) refer to reflections that occur inside the optical detection system, such as reflections from components TX/RX optical interface 360, leakage through optical circulator 354, and the like… The implementations depicted in FIG. 4B facilitate evaluation of the strength of the internal reflection light E.sub.Int(t) and subtraction of this spurious light from the total signal detected by the lidar. As depicted in FIG. 4B, additional local oscillator copies of the light beams can be maintained on the lidar device (e.g., using beam splitters 412, 414, 416, and 418)… Since the strength of the internal reflection beam (characterized by S.sub.Int(t)) is proportional to the strength of the transmitted beam (as both are driven by the same light source 302), the electrical signal S.sub.LO(t) also provides information about the electrical signal S.sub.Int(t) representative of the internal reflection, S.sub.Int(t)=αS.sub.LO(t−τ′), with some coefficient α that is also subject to empirical evaluation (e.g., experimentation). The time delay τ′ may arise in the course of beam propagation through various components of the optical system, e.g., optical modulators 330 and 331, optical combiner 340, amplifier 350, beam splitter 418, and so on. Correspondingly, by detecting E.sub.LO(t), second section 380-2 can generate an electrical signal that is representative of the strength of the internal reflections, αS.sub.LO (t). Each of the two sections of coherent detection stage 380 can output the respective generated electrical signals to a corresponding ADC (e.g., ADC 384 or ADC 386). The outputted digitized signals can be processed by DSP 390, which determines the difference S.sub.Tar(t)+S.sub.Int(t)−αS.sub.LO(t−τ′) and further determines the value of the scaling factor α and time delay τ′ (e.g., by analyzing correlations between S.sub.Tar(t)+S.sub.Int(t) and S.sub.LO(t)) that cancels the spurious signal component, S.sub.Int(t)−αS.sub.LO(t−τ′)=0. Examiner Note: While Piggott does not explicitly recite the specific range of 50% to 100% for the reference signal’s travel time relative to the misdirected signal’s path, the determination of the time delay is disclosed as being subject to “empirical evaluation (e.g., experimentation).” It would have been obvious to a person of ordinary skill in the art to optimize the reference path delay to effectively cancel the internal reflection signal, as the 50% to 100% range constitutes a predictable design optimization for ensuring the reference signal temporal overlap aligns with the internal reflection path for a maximum noise suppression).
Koonath (as previously modified by Forsman) and Piggott are considered to be analogous to the claimed invention because they are both in the same field of LIDAR and optical sensing systems. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have modified the reference signal path configuration of Koonath (as previously modified by Forsman) to include the specific path-length delay parameters disclosed by Piggott with a reasonable expectation of success. This modification would have been motivated by the desire to effectively identify and subtract spurious internal reflections from the LIDAR detection signal. By integrating Piggott’s teaching of using a delayed reference signal to cancel internal reflection components into Koonath (as previously modified by Forsman)’s LIDAR architecture, the system can achieve more accurate signal processing. A person of ordinary skill in the art would recognize that optimizing the path-length delay within the 50-100% range would yield the predictable result of maximum noise suppression and enhanced signal clarity.
Claim 8 is rejected under 35 U.S.C. 103 as being unpatentable over Koonath et al. (US 2022/0113390) and Forsman et al (US 2003/00183603) in further view of Jensen et al. (US 2020/0116863 A1).
Regarding Claim 8, Koonath is not relied upon as teaching that the LIDAR system includes a high-pass filter that receives an electronic version of the composite signal.
However, Jensen teaches that the LIDAR system includes a high-pass filter that receives an electronic version of the composite signal ([0036] FIG. 5 embodiments illustrate the coupling of a portion of the output optical signal with the reflected input optical signal and the local oscillator light and employing a high pass filter 49 to provide the detection signal. In these embodiments, light from the local oscillator 32, reflected light, and transmission (fractional) light are all combine through one or more combiners 34 in the optical-electrical converter 36. An offset in frequency of the local oscillator 32 from the average transmit frequency to approximately in the middle of the electrical frequency band (channel) may be used to create, by the optical-electrical converter 36, the linear amplifier and high pass filter, a current I proportional to E.sub.lo*(E.sub.t+E.sub.r), where E.sub.lo, E.sub.t, & E.sub.r denotes the electrical field of the local oscillator, transmitted light, and reflected light, respectively).
Koonath (as previously modified by Forsman) and Jensen are considered to be analogous to the claimed invention because they are both in the same field of LIDAR and optical sensing systems. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have modified the LIDAR system of Koonath to include the high-pass filter configuration taught by Jensen with a reasonable expectation of success. This modification would have been motivated by the desire to improve signal processing by filtering out undesired low-frequency noise or DC components from the electronic composite signal. By integrating Jensen’s teaching of a high-pass filter into Koonath’s LIDAR architecture, the system can provide a cleaner, more refined detection signal. A person of ordinary skill in the art would recognize that utilizing a high-pass filter in this manner would yield the predictable result of increased signal-to-noise ratio and improved fidelity in the captured LIDAR data.
Claim 16 is rejected under 35 U.S.C. 103 as being unpatentable over Koonath et al. (US 2022/0113390) in view of Piggott et al. (US 2022/0187458 A1).
Regarding Claim 16, Koonath teaches a system ([Abstract] A LIDAR system), comprising:
a LIDAR system that includes a signal splitter configured to receive an outgoing LIDAR signal ([0025] The splitter 22 moves a portion of the light source signal from the utility waveguide 12 onto a reference waveguide 24 as a first reference signal . The reference waveguide 24 carries the first reference signal to the processing unit 20 for further processing),
the LIDAR system being configured to transmit a system output signal from the LIDAR system, the system output signal including light from the outgoing LIDAR signal received by the splitter ([0022] The utility waveguide 12 terminates at a facet 14 and carries the outgoing LIDAR signal to the facet 14. The facet 14 can be positioned such that the outgoing LIDAR signal traveling through the facet 14 exits the LIDAR chip and serves as a LIDAR output signal);
the LIDAR system including a light signal combiner configured to combine light that returns to the LIDAR system from the system output signal with light from a reference signal so as to generate a composite signal beating at a composite beat frequency ([0024] Light from the system return signal can be carried in a first LIDAR input signal that is received by the LIDAR chip. In some instances, a portion of the system return signal can serve as the first LIDAR input signal. The first LIDAR input signals enters a comparative waveguide 16 through the facet 18 and serves as a first comparative signal [0032] As will be described in more detail below, the first processing unit 20 and the second processing unit 40 each combines a comparative signal with a reference signal to form a composite signal that carries LIDAR data for a sample region on the field of view [0068] Due to the difference in frequencies between the comparative signal contribution and the reference signal contribution, the composite signal is beating between the comparative signal contribution and the reference signal contribution),
the reference signal including light from the outgoing LIIDAR signal received by the splitter ([0025] The splitter 22 moves a portion of the light source signal from the utility waveguide 12 onto a reference waveguide 24 as a first reference signal . The reference waveguide 24 carries the first reference signal to the processing unit 20 for further processing;
the splitter being configured to output a portion of the outgoing LIDAR signal that travels an optical pathway from the splitter to a location where the portion of the outgoing LIDAR signal is transmitted from the LIDAR system as the system output signal ([0022] The utility waveguide 12 terminates at a facet 14 and carries the outgoing LIDAR signal to the facet 14. The facet 14 can be positioned such that the outgoing LIDAR signal traveling through the facet 14 exits the LIDAR chip and serves as a LIDAR output signal),
the optical pathway from the splitter to the location where the portion of the outgoing LIDAR signal is transmitted from the LIDAR system including a misdirection source that reflects a misdirected portion of the first portion of the outgoing LIDAR signal that reflects a misdirected portion of the first portion of the outgoing LIDAR signal that serves as a misdirected signal, the misdirected signal being received at the light signal combiner ([0082]-[0083] The system peaks occur as a result of misdirected light from the outgoing LIDAR signal being included in the composite signal without traveling the LIDAR path that is designed for the signals to travel through the LIDAR system. The light from the outgoing LIDAR signal that does not travel the LIDAR path can be considered a misdirected signal. In some instances, the misdirected signal does not leave the LIDAR assembly or the LIDAR system. Accordingly, light from the misdirected signal is often not included in the system output signal. As a result, light from the misdirected light is often not reflected by an object located in a sample region. Example sources of a misdirected signal (misdirection sources) include, but are not limited to, reflections, cross talk between optical components in the LIDAR system, and light scattered by component(s) of the LIDAR system).
Koonath is not relied upon as teaching that the LIDAR system constructed such that for a time for the reference signal to travel from the splitter to the light signal combiner is greater than or equal to 50% and less than or equal to 100% of a time for flight in the misdirected signal to travel from the splitter, to the misdirection source, and to the light signal combiner.
However, Piggott teaches the LIDAR system constructed such that for a time for the reference signal to travel from the splitter to the light signal combiner is greater than or equal to 50% and less than or equal to 100% of a time for flight in the misdirected signal to travel from the splitter, to the misdirection source, and to the light signal combiner ([0085] FIG. 4B is a block diagram illustrating an example implementation of an optical sensing system 403 with frequency multiplexing and efficient detection of targets in the presence of internal reflection… Internal reflections, (close-up returns, back reflections, etc.) refer to reflections that occur inside the optical detection system, such as reflections from components TX/RX optical interface 360, leakage through optical circulator 354, and the like… The implementations depicted in FIG. 4B facilitate evaluation of the strength of the internal reflection light E.sub.Int(t) and subtraction of this spurious light from the total signal detected by the lidar. As depicted in FIG. 4B, additional local oscillator copies of the light beams can be maintained on the lidar device (e.g., using beam splitters 412, 414, 416, and 418)… Since the strength of the internal reflection beam (characterized by S.sub.Int(t)) is proportional to the strength of the transmitted beam (as both are driven by the same light source 302), the electrical signal S.sub.LO(t) also provides information about the electrical signal S.sub.Int(t) representative of the internal reflection, S.sub.Int(t)=αS.sub.LO(t−τ′), with some coefficient α that is also subject to empirical evaluation (e.g., experimentation). The time delay τ′ may arise in the course of beam propagation through various components of the optical system, e.g., optical modulators 330 and 331, optical combiner 340, amplifier 350, beam splitter 418, and so on. Correspondingly, by detecting E.sub.LO(t), second section 380-2 can generate an electrical signal that is representative of the strength of the internal reflections, αS.sub.LO (t). Each of the two sections of coherent detection stage 380 can output the respective generated electrical signals to a corresponding ADC (e.g., ADC 384 or ADC 386). The outputted digitized signals can be processed by DSP 390, which determines the difference S.sub.Tar(t)+S.sub.Int(t)−αS.sub.LO(t−τ′) and further determines the value of the scaling factor α and time delay τ′ (e.g., by analyzing correlations between S.sub.Tar(t)+S.sub.Int(t) and S.sub.LO(t)) that cancels the spurious signal component, S.sub.Int(t)−αS.sub.LO(t−τ′)=0. Examiner Note: While Piggott does not explicitly recite the specific range of 50% to 100% for the reference signal’s travel time relative to the misdirected signal’s path, the determination of the time delay is disclosed as being subject to “empirical evaluation (e.g., experimentation).” It would have been obvious to a person of ordinary skill in the art to optimize the reference path delay to effectively cancel the internal reflection signal, as the 50% to 100% range constitutes a predictable design optimization for ensuring the reference signal temporal overlap aligns with the internal reflection path for a maximum noise suppression).
Koonath and Piggott are considered to be analogous to the claimed invention because they are both in the same field of LIDAR and optical sensing systems. Therefore, it would have been obvious to a person of ordinary skill in the art before the effective filing date of the claimed invention to have modified the reference signal path configuration of Koonath to include the specific path-length delay parameters disclosed by Piggott with a reasonable expectation of success. This modification would have been motivated by the desire to effectively identify and subtract spurious internal reflections from the LIDAR detection signal. By integrating Piggott’s teaching of using a delayed reference signal to cancel internal reflection components into Koonath’s LIDAR architecture, the system can achieve more accurate signal processing. A person of ordinary skill in the art would recognize that optimizing the path-length delay within the 50-100% range would yield the predictable result of maximum noise suppression and enhanced signal clarity.
Conclusion
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Helal Algahaim can be reached at (571) 272-9358. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/E.H.H./Patent Examiner, Art Unit 3645
/HELAL A ALGAHAIM/SPE , Art Unit 3645
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