Optical manifold for lidar applications

Abstract

To provide a LIDAR system that provides reliability, flexibility, and maintainability needed for being commercially adopted.SOLUTION: An optical manifold has multiple cores that each generates an outgoing LIDAR signal carrying one or more channels. Scanning heads are located apart from the manifold. Each scanning head is associated with one of the cores, and is configured so as to receive the outgoing LIDAR signal from the associated core. Each scanning head is configured so that respective scanning heads transmit one or more LIDAR output signals carrying light from a different one channel, and so that each different LIDAR output signal travels away from the scanning head in a different direction. A core electronic circuit is configured to tune a property of the outgoing LIDAR signal such that the tuning of the property causes the one or more LIDAR output signals to change in a direction travelling away from the scanning head associated with the core electronic circuit.SELECTED DRAWING: Figure 5

Description

Related Applications

[0001] This application was filed on November 21, 2018, with the title of the invention being "Optical Manifold for LIDAR Applications", and claims the benefit of U.S. Provisional Patent Application No. 62 / 770,415, which is hereby incorporated by reference in its entirety.

Technical Field

[0002] The present invention relates to an optical device. In particular, the present invention relates to a LIDAR chip.

Background Art

[0003] A LIDAR (Light Detection and Ranging) sensor is used to construct a 3D image of a target scene by illuminating the scene with a LIDAR output signal and measuring the characteristics of the reflected LIDAR input signal. Frequency Modulated Continuous Wave (FMCW) is an example of a coherent detection method that can be used in LIDAR applications. The FMCW technology exhibits reduced sensitivity to ambient light and light from other LIDAR systems.

Summary of the Invention

[0004] LIDAR systems are being adapted for increasingly complex applications such as ADAS (Advanced Driver Assistance Systems) and AR (Augmented Reality). However, LIDAR systems that provide the levels of reliability, flexibility, and maintainability required for commercial adoption have not yet been introduced. As a result, improved LIDAR systems are needed.

Problems to be Solved by the Invention

[0005] The LIDAR system has an optical manifold having a plurality of cores each generating an outgoing LIDAR signal that carries one or more channels. The system also has a scanning head disposed away from the optical manifold. Each scanning head is associated with one of the cores and is configured to receive the outgoing LIDAR signal from the associated core. The scanning head is configured to transmit one or more LIDAR output signals each containing light from a different one of the channels and to transmit the different LIDAR output signals away from the scanning head in different directions. Each of the cores is associated with different core electronics. The core electronics are configured to adjust the characteristics of one of the outgoing LIDAR signals such that the adjustment of the characteristics changes the direction in which the one or more LIDAR output signals travel away from the scanning head associated with the core electronics.

[0006] The LIDAR system has an optical manifold having a housing in which a plurality of cores are arranged, each generating an outgoing LIDAR signal that carriers one or more channels. The system also has a scanning head disposed away from the optical manifold. The scanning head is associated with one of the cores respectively. The scanning head is configured to receive an outgoing LIDAR signal from the core with which each scanning head is associated. The scanning head is configured to transmit one or more LIDAR output signals including light from different ones of the channels. The LIDAR output signals are transmitted such that each of the different LIDAR output signals travels away from the scanning head in a different direction. The cores are respectively included in different core cards. One of the core cards is a first core card connected to a first connector within the housing. A second core card can be located outside the housing but is configured to be connected to the first connector. The second core card is configured to generate an outgoing LIDAR signal that carriers one or more second channels having optical characteristics different from one or more channels of the outgoing LIDAR signal generated by the first core.

[0007] A method of operating an optical manifold includes arranging a plurality of cores inside an optical manifold housing. Each of the cores is configured to generate an output LIDAR signal that carriers one or more channels. Each of the cores is associated with a scanning head disposed away from the optical manifold. The scanning head is configured to receive an outgoing LIDAR signal from the core with which each scanning head is associated. One of the cores is a first core. The method also includes replacing the first core with a second core. The second core is configured to generate an outgoing LIDAR signal that carriers one or more second channels having optical characteristics different from one or more channels of the outgoing LIDAR signal generated by the first core.

Brief Description of the Drawings

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[0023] A LIDAR system has a manifold and a plurality of scanning heads. The manifold can hold a plurality of LIDAR core cards that each generate an outgoing LIDAR signal that carries one or more different channels. Different scanning heads can receive the outgoing LIDAR signal from different LIDAR core cards. Each scanning head can be configured to output one or more LIDAR output signals having light from the outgoing LIDAR signal received by the scanning head.

[0024] The LIDAR core card can modify the characteristics of the emitted LIDAR signal so that the direction in which the LIDAR output signal travels away from the LIDAR system changes. The LIDAR core card can use this change in direction to scan the LIDAR output signal across multiple different sample regions of the field of view. Further, the LIDAR core card can have electronic circuitry that utilizes the light from the LIDAR output signal to generate LIDAR data (radial velocity between the reflecting object and the LIDAR system and / or distance) for each sample region. A manifold having these LIDAR core cards can be located away from all or part of the scanning head. Since the components of the LIDAR core card can be the least rugged components of the LIDAR system, locating the manifold away from the scanning head can place the less rugged components of the LIDAR system in a safe location. For example, the manifold and the LIDAR core cards can be located in a place protected from various atmospheric influences such as weather. The ability to place sensitive components of the LIDAR system in a safe location improves the reliability of the LIDAR system.

[0025] The manifold can be configured so that LIDAR core cards can be easily exchanged with other LIDAR core cards. This exchange can be done in response to a failure or malfunction of a LIDAR core card. As a result, the compatibility of the LIDAR core cards makes it easier to maintain the LIDAR system over time. Additionally, or alternatively, various components of the LIDAR system can be split between the manifold and the scanning head so that a replacement LIDAR core card can have a different functionality than the previous LIDAR core card while still operating with the same scanning head. For example, a replacement LIDAR core card can generate an emitted LIDAR signal that carries a different number of channels, channels having different wavelengths, and / or channels having different waveforms. The ability to easily exchange LIDAR core cards increases the flexibility of the LIDAR system.

[0026] FIG. 1 is a plan view of a LIDAR system having a LIDAR chip with a component assembly 8 having a laser cavity. The laser cavity has a gain medium (not shown) for the laser or has a light source 10 that can be configured. The chip also has a cavity waveguide 12 that receives an optical signal from the light source 10. The light source can be disposed in a recess 13, and by optically aligning the facets of the light source with the facets of the cavity waveguide 12, the light source and the cavity waveguide 12 can exchange optical signals. The cavity waveguide 12 conveys the optical signal to a partial feedback device 14. The illustrated partial feedback device 14 is an optical grating such as a Bragg grating. However, other partial feedback devices 14 can be used, for example, a mirror can be used with an echelle diffraction grating and an arrayed waveguide grating.

[0027] The partial feedback device 14 returns a returned portion of the optical signal to the cavity waveguide 12 as a return signal. For example, the cavity waveguide 12 returns the return signal to the light source 10 such that the returned portion of the optical signal travels through the gain medium. The light source 10 is configured to add at least a portion of the return signal to the optical signal received in the cavity waveguide 12. For example, the light source 10 can have a high, total, or partial reflector 15 that reflects the return signal received from the gain medium back to the gain medium. As a result, light resonates between the partial feedback device 14 and the reflector 15, and a distributed Bragg reflector (DBR) laser cavity can be formed. The DBR laser cavity has an essentially narrower linewidth and a longer coherence length than a DFB laser, and thus improves performance when an object reflecting the LIDAR output signal from the chip is located further away from the chip.

[0028] The partial return device 14 passes a part of the optical signal received from the cavity waveguide 12 to the utility waveguide 16 included in the chip. The part of the optical signal received by the utility waveguide 16 from the partial return device 14 functions as the output of the laser cavity. The output of the laser cavity functions as the emitted LIDAR signal of the utility waveguide 16. The utility waveguide 16 terminates at the facet 18 and conveys the emitted LIDAR signal to the facet 18. The facet 18 can be arranged so that the emitted LIDAR signal passing through the facet 18 exits the chip and functions as the LIDAR output signal. For example, the facet 18 can be arranged at the edge of the chip so that the emitted LIDAR signal passing through the facet 18 exits the chip and functions as the LIDAR output signal.

[0029] The LIDAR output signal travels away from the chip and is reflected by an object in the path of the LIDAR signal. The reflected signal travels away from the object. At least a part of the reflected signal returns to the facet 18 of the utility waveguide 16. Therefore, a part of the reflected signal can enter the utility waveguide 16 through the facet 18 and function as the LIDAR input signal guided by the utility waveguide 16.

[0030] The chip has a data branch 24 where an optical signal to be processed for LIDAR data is generated. The data branch has an optical coupler 26 that moves a part of the optical signal from the utility waveguide 16 to the data branch. For example, the optical coupler 26 couples a part of the emitted LIDAR signal from the utility waveguide 16 to the reference waveguide 27 as a reference signal. The reference waveguide 27 conveys the reference signal to the optical coupling component 28.

[0031] The optical coupler 26 also couples a portion of the LIDAR input signal from the utility waveguide 16 to the comparison waveguide 30 as a comparison signal. The comparison signal has at least a portion of the light from the LIDAR input signal. The comparison signal can exclude the light from the reference optical signal. The comparison waveguide 30 conveys the comparison signal to the optical coupling component 28.

[0032] The illustrated optical coupler 26 results from positioning the utility waveguide 16 sufficiently close to the reference waveguide 27 and the comparison waveguide 30 such that light from the utility waveguide 16 is coupled to the reference waveguide 27 and the comparison waveguide 30. However, other signal tap components can be used to transfer a portion of the optical signal from the utility waveguide 16 to the reference waveguide 27 and the comparison waveguide 30. Examples of suitable signal tap components include, but are not limited to, y-branches, multi-mode interference couplers (MMIs), and integrated optical circulators.

[0033] The optical coupling component 28 couples the comparison signal and the reference signal into a combined signal. The reference signal has the light from the emitted LIDAR signal. For example, the reference signal can function as a sample of the emitted LIDAR signal. The reference signal can exclude the light from the LIDAR output signal and the LIDAR input signal. In contrast, the comparison signal light has the light from the LIDAR input signal. For example, the comparison signal can function as a sample of the LIDAR input signal. Thus, the comparison signal is reflected by an object away from the chip while the LIDAR output signal is not. As the chip and the reflecting object move relative to each other, the comparison signal and the reference signal have different frequencies due to the Doppler effect. As a result, a beat occurs between the comparison signal and the reference signal.

[0034] The optical coupling component 28 also splits the obtained composite sample signal into a first detector waveguide 36 and a second detector waveguide 38. The first detector waveguide 36 conveys a first portion of the composite sample signal to a first optical sensor 40 that converts the first portion of the composite sample signal into a first electrical signal. The second detector waveguide 38 conveys a second portion of the composite sample signal to a second optical sensor 42 that converts the second portion of the composite sample signal into a second electrical signal. Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0035] The optical coupling component 28, the first optical sensor 40, and the second optical sensor 42 can be connected as a balanced optical detector that outputs an electrical data signal. For example, the optical coupling component 28, the first optical sensor 40, and the second optical sensor 42 can be connected such that the DC components of the signal photocurrents cancel each other out, improving the detection sensitivity. A method suitable for connecting the first optical sensor 40 and the second optical sensor 42 as a balanced optical detector includes a series connection of the first optical sensor 40 and the second optical sensor 42. In one example, both the first optical sensor 40 and the second optical sensor 42 are avalanche photodiodes connected in series. Balanced optical detection is desirable for detecting small signal fluctuations.

[0036] An example of a suitable optical coupling component 28 is a multi-mode interference (MMI) device such as a 2×2 MMI device. Other suitable optical coupling components 28 include, but are not limited to, adiabatic splitters and directional couplers. In some examples, the functions of the illustrated optical coupling component 28 are performed by one or more optical components or a set of optical components.

[0037] A single optical sensor can replace the first optical sensor 40 and the second optical sensor 42 and can output a data signal. When the single optical sensor replaces the first optical sensor 40 and the second optical sensor 42, the optical coupling component 28 need not have an optical splitting function. As a result, the illustrated optical coupling component 28 can be a 2×1 optical coupling component instead of the illustrated 2×1 optical coupling component. For example, the illustrated optical coupling component can be a 2×1 MMI device. In these examples, the chip has a single detector waveguide that conveys a composite sample signal to the optical sensor.

[0038] The data branch has a data optical attenuator 44 disposed along the comparison waveguide 30, and the data optical attenuator 44 can be operated to attenuate the comparison signal of the comparison waveguide 30. The chip also has an output optical attenuator 46 disposed along the utility waveguide 16, and the output optical attenuator 46 can be operated to attenuate the output LIDAR signal of the utility waveguide 16. Suitable attenuators for the data optical attenuator 44 and / or the output optical attenuator 46 are configured to attenuate the intensity of the optical signal. Examples of suitable attenuators configured to attenuate the intensity of the optical signal include PIN diodes based on carrier injection, electro-absorption modulators, and Mach-Zehnder (MZ) modulators.

[0039] The chip also has a sampling directional coupler 50 that couples a portion of the comparison signal from the comparison waveguide 30 to the sampling waveguide 52. The coupled portion of the comparison signal functions as a sampling signal. The sampling waveguide 52 conveys the sampling signal to the sampling optical sensor 54. FIG. 1 shows the sampling directional coupler 50 that moves a portion of the comparison signal to the sampling waveguide 52, but other signal tap components can be used to move a portion of the comparison signal from the comparison waveguide 30 to the sampling waveguide 52. Examples of suitable signal tap components include, but are not limited to, y-branches and MMIs.

[0040] The chip has a control branch 55 for controlling the operation of the laser cavity. The control branch has a directional coupler 56 that moves a portion of the emitted LIDAR signal from the utility waveguide 16 to the control waveguide 57. The combined portion of the emitted LIDAR signal functions as a tapped signal. FIG. 1 shows the directional coupler 56 that moves a portion of the emitted LIDAR signal to the control waveguide 57, but other signal tap components can be used to move a portion of the emitted LIDAR signal from the utility waveguide 16 onto the control waveguide 57. Examples of suitable signal tap components include, but are not limited to, y-branches and MMIs.

[0041] The control waveguide 57 conveys the tap signal to an interferometer 58 that splits the tap signal and recombines different portions of the tap signal with a phase difference between the portions of the tap signal. The illustrated interferometer 58 is a Mach-Zehnder interferometer, but other interferometers can be used.

[0042] The interferometer 58 outputs a control optical signal to an interferometer waveguide 60. The interferometer waveguide 60 conveys the control optical signal to a control optical sensor 61 that converts the control optical signal into an electrical signal that functions as an electrical control signal. The interferometer signal has an intensity that is a function of the frequency of the emitted LIDAR signal. For example, a Mach-Zehnder interferometer outputs a sinusoidal control optical signal having a fringe pattern. A change in the frequency of the emitted LIDAR signal causes a change in the frequency of the control optical signal. Accordingly, the frequency of the electrical control signal output from the control optical sensor 61 is a function of the frequency of the emitted LIDAR signal. Other detection mechanisms can be used instead of the control optical sensor 61. For example, the control optical sensor 61 can be replaced with a balanced optical detector arranged as an optical coupling component 28, a first optical sensor 40, and a second optical sensor 42.

[0043] The electronic circuit 62 can operate one or more components on the chip. For example, the electronic circuit 62 can communicate electrically with the light source 10, the data optical attenuator 44, the output optical attenuator 46, the first optical sensor 40, the second optical sensor 42, the sampling optical sensor 54, and the control optical sensor 61, and can control the operations. Although the electronic circuit 62 is shown as being separate from the chip, all or part of the electronic circuit can be included in the chip. For example, the chip can have a conductor that connects the first optical sensor 40 in series with the second optical sensor 42.

[0044] During operation of the chip, the electronic circuit 62 operates the light source 10 so that the laser cavity outputs an emitted LIDAR signal. Next, the electronic circuit 62 operates the chip through a series of cycles in which each cycle generates LIDAR data (radial velocity and / or distance between the reflecting object and the LIDAR chip) regarding the sample region of the field of view. During each cycle, the data signal is sampled multiple times. Between each sample, the electronic circuit adjusts the frequency of the emitted LIDAR signal. As will be described in more detail below, the electronic circuit can use the output from the control branch to control the frequency of the emitted LIDAR signal as a function of time, as is known to the electronic circuit. In some examples, a cycle has multiple periods. For example, a cycle can have a first period and a second period. During the first period, the electronic circuit 62 can increase the frequency of the emitted LIDAR signal, and during the second period, the electronic circuit 62 can decrease the frequency of the emitted LIDAR signal. In some cases, the increase is linear and the decrease is linear. For example, the laser cavity can be configured to output an emitted LIDAR signal (and thus a LIDAR output signal) having a wavelength of 1550 nm. During the first period, the electronic circuit 62 can increase the frequency of the emitted LIDAR signal (and thus the LIDAR output signal) so that the wavelength decreases from 1550 nm to 1459.98 nm, and then can decrease the frequency of the emitted LIDAR signal so that the wavelength increases from 1459.98 nm to 1550 nm.

[0045] When the frequency of the emitted LIDAR signal increases during the first period, the LIDAR output signal travels away from the chip and then returns to the chip as the LIDAR input signal. A part of the LIDAR input signal becomes the comparison signal. While the LIDAR output signal and the LIDAR input signal are traveling between the chip and the reflecting object, the frequency of the emitted LIDAR signal continues to increase. Since a part of the emitted LIDAR signal becomes the reference signal, the frequency of the reference signal continues to increase. As a result, the comparison signal enters the optical coupling component at a frequency lower than the reference signal that is incident on the optical coupling component simultaneously. Furthermore, the farther the reflecting object is placed from the chip, the more the frequency of the reference signal increases before the LIDAR input signal returns to the chip. Therefore, the greater the difference between the frequency of the comparison signal and the frequency of the reference signal, the farther the reflecting object is from the chip. As a result, the difference between the frequency of the comparison signal and the frequency of the reference signal is a function of the distance between the chip and the reflecting object.

[0046] For the same reason, when the frequency of the emitted LIDAR signal decreases during the second period, the comparison signal enters the optical coupling component at a frequency higher than the reference signal that is incident on the optical coupling component simultaneously, and the difference between the frequency of the comparison signal and the frequency of the reference signal during the second period is also a function of the distance between the chip and the reflecting object.

[0047] In some examples, since the relative movement of the chip and the reflective object also affects the frequency of the comparison signal, the difference between the frequency of the comparison signal and the frequency of the reference signal can also be a function of the Doppler effect. For example, when the chip moves towards or away from the reflective object, and / or when the reflective object moves towards or away from the chip, the Doppler effect may affect the frequency of the comparison signal. Since the frequency of the comparison signal is a function of the speed at which the reflective object moves towards or away from the chip and / or the speed at which the chip moves towards or away from the reflective object, the difference between the frequency of the comparison signal and the frequency of the reference signal is also a function of the speed at which the reflective object moves towards or away from the chip and / or the speed at which the chip moves towards or away from the reflective object. Therefore, the difference between the frequency of the comparison signal and the frequency of the reference signal is a function of the distance between the chip and the reflective object and is also a function of the Doppler effect.

[0048] The composite sample signal and the data signal each effectively compare the comparison signal and the reference signal. For example, an optical coupling component combines the comparison signal and the reference signal, and since these signals have different frequencies, there is a beat between the comparison signal and the reference signal. Therefore, the composite sample signal and the data signal have a beat frequency related to the frequency difference between the comparison signal and the reference signal, and the beat frequency can be used to determine the difference in frequency between the comparison signal and the reference signal. If the beat frequency for the composite sample signal and / or the data signal is higher, it indicates a greater difference between the frequency of the comparison signal and the frequency of the reference signal. As a result, the beat frequency of the data signal is a function of the distance between the chip and the reflective object and is also a function of the Doppler effect.

[0049] As described above, the ringing frequency is a function of two unknowns, the distance between the chip and the reflecting object, and the relative velocity between the chip and the reflecting object (i.e., the contribution of the Doppler effect). The change in the frequency difference (Δf) between the comparison signal and the reference signal is given by Δf = 2Δvf / c, where f is the frequency of the LIDAR output signal, and thus the reference signal, Δv is the relative velocity between the chip and the reflecting object, and c is the speed of light in air. By using a plurality of different samples, the electronic circuit 62 can solve the two unknowns. For example, the ringing frequency determined for a first period is related to the unknown distance and the Doppler contribution, and the ringing frequency determined for a second period is also related to the unknown distance and the Doppler contribution. By being able to utilize the two relationships, the electronic circuit 62 can solve the two unknowns. Thus, the distance between the chip and the reflecting object can be determined without being affected by the Doppler effect. Further, in some examples, the electronic circuit 62 uses this distance in combination with the Doppler effect to determine the velocity of the reflecting object moving towards or away from the chip.

[0050] When the relative velocity between the target and the source is zero or very small, the contribution of the Doppler effect to the ringing frequency is essentially zero. In these examples, since the Doppler effect does not substantially contribute to the ringing frequency, the electronic circuit 62 can take only the first period to determine the distance between the chip and the reflecting object.

[0051] During operation, the electronic circuit 62 can adjust the frequency of the emitted LIDAR signal according to the electrical control signal from the control optical sensor 61. As described above, the magnitude of the electrical control signal output from the control optical sensor 61 is a function of the frequency of the emitted LIDAR signal. Therefore, the electronic circuit 62 can adjust the frequency of the emitted LIDAR signal according to the magnitude of the control. For example, while changing the frequency of the emitted LIDAR signal during one sample, the electronic circuit 62 can have an appropriate range of values regarding the magnitude of the electrical control signal as a function of time. At multiple different times during the sample, the electronic circuit 62 can compare the magnitude of the electrical control signal with the range of values associated with the current time of the sample. If the magnitude of the electrical control signal indicates that the frequency of the emitted LIDAR signal is outside the associated range of the magnitude of the electrical control signal, the electronic circuit 62 can operate the light source 10 so that the frequency of the emitted LIDAR signal falls within the associated range. If the magnitude of the electrical control signal indicates that the frequency of the emitted LIDAR signal is within the associated range of the magnitude of the electrical control signal, the electronic circuit 62 does not change the frequency of the emitted LIDAR signal.

[0052] During operation, the electronic circuit 62 can adjust the level of attenuation provided by the output optical attenuator 46 according to the sampling signal from the sampling optical sensor 54. For example, the electronic circuit 62 can operate the output optical attenuator 46 to decrease the attenuation level according to the magnitude of the sampling signal exceeding the first signal threshold and / or to decrease the magnitude of the power drop according to the magnitude of the sampling signal falling below the second signal threshold.

[0053] In some examples, the electronic circuit 62 adjusts the level of attenuation provided by the output optical attenuator 46 to prevent or reduce the impact of back reflection on the performance of the laser cavity. For example, the first signal threshold and / or the second signal threshold can be arbitrarily selected to prevent or reduce the impact of retroreflection on the performance of the laser cavity. Back reflection occurs when a portion of the LIDAR input signal returns and enters the laser cavity as a LIDAR signal. In some examples, on the order of 50% of the LIDAR input signal passing through the facet 18 returns to the laser cavity. The return LIDAR signal can affect the performance of the laser cavity when the power of the return LIDAR signal entering the partial return device 14 is lower than ( "power drop") and does not drop below the minimum power drop threshold compared to the power of the outgoing LIDAR signal exiting the partial return device. In the illustrated chip, the minimum power drop threshold can be about 35 dB (0.03%). Thus, the return LIDAR signal can affect the performance of the laser cavity when the power of the return LIDAR signal entering the partial return device 14 is 35 dB or less than the power of the outgoing LIDAR signal exiting the partial return device 14.

[0054] The electronic circuit 62 can operate the output optical attenuator 46 to reduce the impact of low power drop, for example, when the target object is very close, or highly reflective, or both. As is apparent from FIG. 1, the operation of the output optical attenuator 46 to increase the level of attenuation reduces the power of the returned LIDAR signal entering the partial return device 14, and also reduces the power of the LIDAR signal returning from a position away from the partial return device 14. Since the output optical attenuator 46 is arranged away from the partial return device 14, the power of the downlink LIDAR signal exiting the partial return device 14 is not directly affected by the operation of the output optical attenuator 46. As a result, the operation of the output optical attenuator 46 increases the level of attenuation and increases the level of power drop. Therefore, the electronic device can use the optical attenuator 46 to adjust the power drop.

[0055] Furthermore, the magnitude of the sampling signal is associated with the power drop. For example, as is clear from FIG. 1, the magnitude of the sampling signal is associated with the power of the comparison signal. Since the comparison signal is part of the LIDAR input signal, the magnitude of the sampling signal is associated with the power of the LIDAR input signal. This result means that since the return LIDAR signal is part of the lidar input signal, the magnitude of the sampling signal is also associated with the power of the return LIDAR signal. Therefore, the magnitude of the sampling signal is associated with the power drop.

[0056] Since the magnitude of the sampling signal is associated with the power drop, the electronic circuit 62 can use the magnitude of the sampling signal to operate the output optical attenuator and maintain the magnitude of the comparison signal at a power within the target range. For example, the electronic circuit 62 can operate the output optical attenuator 46 to increase the magnitude of the power drop in response to a sampling signal indicating that the magnitude of the power drop is below a first threshold, and / or the electronic circuit 62 can operate the output optical attenuator 46 to decrease the magnitude of the power drop in response to a sampling signal indicating that the magnitude of the power drop is above a second threshold. In some examples, the first threshold is above the minimum power drop threshold. In one example, the electronic circuit 62 can operate the output optical attenuator 46 to increase the magnitude of the power drop in response to a magnitude of the sampling signal exceeding a first signal threshold, and / or decrease the magnitude of the power drop in response to a magnitude of the sampling signal below a second signal threshold. The identification of the values of one, two, three, or four variables selected from the group consisting of the first threshold, the second threshold, the first signal threshold, and the second signal threshold can be determined from the calibration of the optical chip in the setup of the LIDAR chip system.

[0057] The optical sensor may enter a saturation state when the power of the composite optical signal exceeds the power threshold. When the optical sensor enters the saturation state, the magnitude of the data signal reaches a maximum value that does not increase despite further increases in the power of the composite optical signal exceeding the power threshold. Therefore, when the power of the composite optical signal exceeds the power threshold, data may be lost. During operation, the electronic circuit 62 can adjust the level of attenuation provided by the data optical attenuator 44 to maintain the power of the composite optical signal below the power threshold.

[0058] As is apparent from FIG. 1, the magnitude of the sampling signal is related to the power of the comparison signal. Therefore, the electronic circuit 62 can operate the data optical attenuator 44 in response to the output from the sampling signal. For example, the electronic circuit 62 can operate the data optical attenuator to increase the attenuation of the comparison signal when the magnitude of the sampling signal indicates that it exceeds the upper comparison signal threshold, and / or the electronic circuit 62 can operate the data optical attenuator to decrease the attenuation of the comparison signal when the magnitude of the sampling signal indicates that it is below the lower comparison signal threshold. For example, in some examples, the electronic circuit 62 can increase the attenuation of the comparison signal when the magnitude of the sampling signal is greater than or equal to the upper comparison threshold, and / or the electronic circuit 62 can decrease the attenuation of the comparison signal when the magnitude of the sampling signal is less than or equal to the upper comparison signal threshold.

[0059] As described above, the electronic circuit 62 can adjust the level of attenuation provided by the output optical attenuator 46 in response to the sampling signal. In addition to, or alternatively to, adjusting the level of attenuation provided by the output optical attenuator 46 in response to the sampling signal, the electronic circuit 62 can adjust the level of attenuation provided by the data optical attenuator 44 in response to the sampling signal.

[0060] Suitable platforms for the chip include, but are not limited to, silica, indium phosphide, and silicon-on-insulator wafers. FIG. 2 is a cross-sectional view of a portion of a chip composed of a silicon-on-insulator wafer. The silicon-on-insulator (SOI) wafer has a buried layer 80 between a substrate 82 and an optical transmission medium 84. In a silicon-on-insulator wafer, the buried layer is silica, and the substrate and the optical transmission medium are silicon. The substrate of an optical platform such as an SOI wafer can function as the base of the entire chip. For example, the optical components shown in FIG. 1 can be arranged on the upper side and / or the lateral surface of the substrate, or above it.

[0061] A portion of the chip shown in FIG. 2 has a waveguide structure suitable for use with a chip constructed from a silicon-on-insulator wafer. A ridge 86 of the optical transmission medium extends away from a slab region 88 of the optical transmission medium. The optical signal is confined between the top of the ridge and the buried oxide layer.

[0062] The dimensions of the ridge waveguide are labeled in Figure 2. For example, the ridge has a width labeled w and a height labeled h. The thickness of the slab region is labeled T. In LIDAR applications, these dimensions are more important than those used in other applications because they need to use a higher level of optical power. The ridge width (labeled w) is greater than 1 μm and less than 4 μm, the ridge height (labeled h) is greater than 1 μm and less than 4 μm, and the thickness of the slab region is greater than 0.5 μm and less than 3 μm. These dimensions are applicable to the straight or substantially straight portions of the waveguide, the curved portions of the waveguide, and the tapered portions of the waveguide. Thus, these portions of the waveguide are single mode. However, in some examples, while these dimensions apply to the straight or substantially straight portions of the waveguide, the curved portions and / or the tapered portions of the waveguide have dimensions outside of these ranges. For example, the tapered portion of the utility waveguide 16 shown in Figure 1 can have a width and / or height greater than 4 μm and can be in the range from 4 μm to 12 μm. Additionally, or alternatively, the curved portions of the waveguide may have a reduced slab thickness to reduce optical losses within the curve. For example, the curved portion of the waveguide can have a ridge extending away from a slab region having a thickness of 0.0 μm or more and less than 0.5 μm. The above dimensions generally provide straight or substantially straight portions of the waveguide having a single mode structure, while they can result in tapered and / or curved portions that are multi mode. The coupling between the multi mode geometry and the single mode geometry can be done using a taper that does not substantially excite higher order modes. Thus, the waveguide can be configured such that the signal carried by the waveguide is carried in single mode even when it is carried in a waveguide portion having multi mode dimensions.The structure of the waveguide in FIG. 2 is suitable for all or part of the waveguides selected from the group consisting of the cavity waveguide 12, the utility waveguide 16, the reference waveguide 27, the comparison waveguide 30, the first detector waveguide 36, the second detector waveguide 38, the sampling waveguide 52, the control waveguide 57, and the interferometer waveguide 60.

[0063] The light source 10 interfaced with the utility waveguide 16 is a component separate from the chip and can then be a gain element attached to the chip. For example, the light source 10 can be a gain element attached to a chip using a flip-chip arrangement.

[0064] When the light source 10 interfaces with the ridge waveguide of a chip composed of a silicon-on-insulator wafer, the use of a flip-chip arrangement is suitable. Examples of suitable interfaces between the flip-chip gain element and the ridge waveguide of a chip constructed from a silicon-on-insulator wafer are described in U.S. Patent No. 9,705,278, issued July 11, 2017, and U.S. Patent No. 5,991,484, issued November 23, 1999, each of which is incorporated herein by reference in its entirety. This configuration is suitable for use as the light source 10. When the light source 10 is a gain element, the electronic circuit 62 can vary the frequency of the emitted LIDAR signal by varying the level of the current applied through the gain element.

[0065] The attenuator can be a component separated from the chip and then attached to the chip. For example, the attenuator can be included in an attenuator chip attached to the chip in a flip-chip arrangement. The use of an attenuator chip is suitable for all or part of the attenuators selected from the group consisting of a data attenuator and a control attenuator.

[0066] Instead of including an attenuator in another component, all or part of the attenuator can be integrated into the chip. For example, an attenuator interfaced with a ridge waveguide of a chip composed of a silicon-on-insulator wafer can be found in U.S. Patent No. 5,908,305, issued on June 1, 1999, the entire content of which is incorporated herein by reference. The use of an attenuator integrated into the chip is suitable for all or part of an optical sensor selected from the group consisting of a data attenuator and a control attenuator.

[0067] An optical sensor interfaced with a waveguide on the chip can be a component separated from the chip and attached to the chip. For example, the optical sensor can be a photodiode or an avalanche photodiode. Examples of suitable optical sensor components include, but are not limited to, an InGaAs PIN photodiode manufactured by Hamamatsu located in Hamamatsu, Japan, or an InGaAs PIN APD (avalanche photodiode) manufactured by Hamamatsu located in Hamamatsu, Japan. These optical sensors can be centrally arranged on the chip as shown in FIG. 1. Alternatively, all or part of the waveguide terminated by the optical sensor can be terminated by a facet 18 arranged at the edge of the chip, and the optical sensor can be attached to the end of the chip on the facet 18 so as to receive the light passing through the facet 18. The use of an optical sensor as a component separate from the chip is suitable for all or part of an optical sensor selected from the group consisting of a first optical sensor 40, a second optical sensor 42, a sampling optical sensor 54, and a control optical sensor 61.

[0068] Instead of an optical sensor being a separate component, all or part of the optical sensor can be integrated into a chip. For example, examples of optical sensors interfaced with ridge waveguides on a chip composed of a silicon-on-insulator wafer can be found in Optics Express Vol.15, No.21, 13965-13971 (2007); U.S. Patent No. 8,093,080 issued on January 10, 2012; U.S. Patent No. 8,242,432 issued on August 14, 2012; and U.S. Patent No. 6,108,472 issued on August 22, 2000, each of which is incorporated herein by reference in its entirety. Using an optical sensor integrated with a chip is suitable for all or part of an optical sensor selected from the group consisting of a first optical sensor 40, a second optical sensor 42, a sampling optical sensor 54, and a control optical sensor 61.

[0069] Configurations of optical gratings integrated into various optical device platforms can be utilized. For example, a Bragg grating can be formed in a ridge waveguide by forming grooves at the top of the ridge and / or on the rear side of the ridge.

[0070] Figure 3 is a schematic diagram of a LIDAR system. The system has a light source 110, such as a laser, that outputs an emitted optical signal. The emitted optical signal has a plurality of different channels, each having a different wavelength. The wavelengths of the channels can be arranged at regular intervals periodically in that the increase in wavelength from one channel to the next is constant or substantially constant. Suitable light sources 110 for generating a plurality of channels having wavelengths arranged at regular intervals periodically include, but are not limited to, a comb laser, a plurality of single-wavelength lasers multiplexed in a single optical waveguide, the light source described in U.S. Patent Application No. 11 / 998,846, Patent No. 7,542,641, and the invention title "Multi-Channel Optical Device" filed on November 30, 2017, the entire disclosure of which is incorporated herein by reference.

[0071] The LIDAR system also has a utility waveguide 112 that receives the emitted optical signal from the light source 110. The modulator 114 is optionally disposed along the utility waveguide 112. The modulator 114 is configured to modulate the emitted optical signal and thus the power of the LIDAR output signal. The electronic circuitry can operate the modulator 114. Thus, the electronic circuitry can modulate the output LIDAR signal and thus the power of the LIDAR output signal. Suitable modulators include, but are not limited to, PIN diode carrier injection devices, Mach-Zehnder modulators, and electro-absorption modulators. When the modulator 114 is configured on a silicon-on-insulator platform, a suitable modulator is disclosed in U.S. Patent Application No. 617,810, filed September 21, 1993, entitled Integrated Silicon PIN Diode Electro-Optic Waveguide, the entire disclosure of which is incorporated herein by reference.

[0072] The amplifier 116 is optionally disposed along the utility waveguide 112. Since the power of the emitted optical signal is distributed among a plurality of channels, it is desirable for the amplifier 116 to provide each channel on the utility waveguide 112 with a desired power level. Suitable amplifiers include, but are not limited to, semiconductor optical amplifiers (SOAs).

[0073] The utility waveguide 112 conveys the emitted optical signal from the modulator 114 to the signal directing component 118. The signal directing component 118 can direct the emitted optical signal to the LIDAR branch 120 and / or the data branch 122. The LIDAR branch outputs the LIDAR output signal and receives the LIDAR input signal. The data branch processes the LIDAR input signal for the generation of LIDAR data (the distance between the source of the LIDAR output signal and the reflecting object and / or the radial velocity).

[0074] The LIDAR branch has a LIDAR signal waveguide 124 that receives at least a portion of the emitted optical signal from the signal directing component 118. The LIDAR signal waveguide 124 terminates at the facet 118 and also conveys the emitted LIDAR signal to the facet 118. The facet 118 can be arranged such that the emitted LIDAR signal traveling through the facet 118 exits the chip and functions as the transmitted LIDAR signal. For example, the facet 118 is arranged at the edge of the chip such that the emitted LIDAR signal traveling through the facet 118 exits the chip and can function as the transmitted LIDAR signal.

[0075] The transmitted LIDAR signal travels away from the chip and is reflected by an object in the path of the transmitted LIDAR signal. The reflected signal travels away from the object. At least a portion of the reflected signal returns to the facet 118. Thus, a portion of the reflected signal can enter the LIDAR signal waveguide 124 through the facet 118 and function as an incident LIDAR signal guided by the LIDAR signal waveguide 124.

[0076] As will be apparent below, the emitted LIDAR signal and the transmitted LIDAR signal can each have one or more LIDAR output signals corresponding to different channels. Thus, the incident LIDAR signal and the reflected signal can each have one or more LIDAR input signals corresponding to different channels.

[0077] The LIDAR signal waveguide 124 conveys the incident LIDAR signal to the signal directing component 118. The signal directing component 118 directs the incident LIDAR signal to the utility waveguide 112 and / or the comparison signal waveguide 128. The portion of the incident LIDAR signal directed to the comparison signal waveguide 128 provides a comparison incident LIDAR signal.

[0078] The comparison signal waveguide 128 conveys the comparison incident LIDAR signal to the comparison demultiplexer 130. When the comparison optical signal has a plurality of channels, the comparison demultiplexer 130 divides the comparison incident LIDAR signal into different comparison signals having different wavelengths. The comparison demultiplexer 130 outputs the comparison signals to different comparison waveguides 132. The comparison waveguides 132 each convey one of the comparison signals to a different processing component 134.

[0079] The signal directing component 118 is configured such that when the signal directing component 118 directs at least a part of the incident LIDAR signal to the comparison waveguide 132, the signal directing component 118 also directs at least a part of the emitted optical signal to the reference signal waveguide 136. The portion of the emitted optical signal received by the reference signal waveguide 136 functions as a reference optical signal.

[0080] The reference signal waveguide 136 conveys the reference optical signal to the reference demultiplexer 138. When the reference optical signal has a plurality of channels, the reference demultiplexer 138 divides the reference optical signal into different reference signals having different wavelengths. The reference demultiplexer 138 outputs the reference signals to different reference waveguides 140. The reference waveguides 140 each convey one of the reference signals to a different one of the processing components 134.

[0081] The comparison waveguide 132 and the reference waveguide 140 are configured such that the comparison signal and the corresponding reference signal are received by the same processing component 134. For example, the comparison waveguide 132 and the reference waveguide 140 are configured such that the reference waveguide and the corresponding reference signal of the same wavelength are received by the same processing component 134.

[0082] As will be described in more detail below, each of the processing components 134 combines the comparison signal with the corresponding reference signal to form a composite signal that conveys LIDAR data regarding the sample region of the field of view. Accordingly, the composite signal can be processed to extract the LIDAR data regarding the sample region.

[0083] The signal directing component 118 can be an optical coupler. When the signal directing component 118 is an optical coupler, the signal directing component 118 directs a first portion of the emitted optical signal to the LIDAR signal waveguide 124 and a second portion of the emitted optical signal to the reference signal waveguide 136, and also directs a first portion of the incident LIDAR signal to the utility waveguide 112 and a second portion of the incident LIDAR signal to the comparison signal waveguide 128. Thus, the second portion of the incident LIDAR signal can function as a comparison incident LIDAR signal, and the second portion of the emitted optical signal can function as a reference optical signal.

[0084] The signal directing component 118 can be an optical switch such as a cross switch. A suitable cross-over switch can be operated in a cross mode or a pass mode. In the pass mode, the emitted optical signal is directed to the LIDAR signal waveguide 124, and the incident LIDAR signal is directed to the utility waveguide 112. In the cross mode, the emitted optical signal is directed to the reference signal waveguide 136, and the incident LIDAR signal is directed to the comparison signal waveguide 128. Thus, the incident LIDAR signal, or a portion of the incident LIDAR signal, can function as a comparison optical signal, and the emitted optical signal, or a portion of the emitted optical signal, can function as a reference optical signal.

[0085] An optical switch such as a cross-over switch can be controlled by an electronic circuit. For example, the electronic circuit can operate the switch such that the switch is in the cross mode or the pass mode. When the LIDAR output signal is transmitted from the LIDAR system, the electronic circuit operates the switch such that the switch is in the pass mode. When the LIDAR input signal is received by the LIDAR system, the electronic circuit operates the switch such that the switch is in the cross mode. The use of the switch can provide a lower level of optical loss than the use of an optical coupler as the signal directing component 118.

[0086] In the above description regarding the operation of the signal directing component 118, the comparison optical signal and the reference optical signal are simultaneously directed towards the data branch. As a result, the processing component 134 can combine each comparison signal with the corresponding reference signal.

[0087] In some examples, the optical amplifier 142 is optionally disposed along the LIDAR signal waveguide 124 and configured to provide amplification of the output optical signal and / or the incident LIDAR signal. Accordingly, the effect of optical loss in the signal directing component 118 can be reduced.

[0088] Light from the laser light source is typically linearly polarized, and thus the LIDAR output signal is also typically linearly polarized. Reflection from the target may change the polarization angle of the return light. Accordingly, the LIDAR input signal can have light when having different linear polarities. For example, a first portion of the LIDAR input signal can have light of a first linear polarity, and a second portion of the LIDAR input signal can have light of a second linear polarity. The intensity of the resulting composite signal is proportional to the square of the cosine of the angle between the comparison signal polarization and the reference signal polarization. When the angle is 90 degrees, the LIDAR data may be lost in the resulting composite signal. As a result, the LIDAR system can be modified to compensate for changes in the polarity of the LIDAR output signal.

[0089] Figures 4A through 4B illustrate an example of a suitable processing component for use in the LIDAR system of FIG. 3. The first splitter 202 splits the reference signal carried in the reference waveguide 140 into a first reference waveguide 210 and a second reference waveguide 208. The first reference waveguide 210 conveys a first portion of the reference signal to the optical coupling component 211. The second reference waveguide 208 conveys a second portion of the reference signal to the second optical coupling component 212.

[0090] The second splitter 200 splits the comparison signal carried to the comparison waveguide 132 into a first comparison waveguide 204 and a second comparison waveguide 206. The first comparison waveguide 204 carries a first portion of the comparison signal to the optical coupling component 211. The second comparison waveguide 208 carries a second portion of the comparison signal to the second optical coupling component 212.

[0091] The second optical coupling component 212 couples the second portion of the comparison signal and the second portion of the reference signal into a second composite signal. Due to the frequency difference between the second portion of the comparison signal and the second portion of the reference signal, the second composite signal ripples between the second portion of the comparison signal and the second portion of the reference signal. The optical coupling component 212 also splits the resulting second composite signal into a first auxiliary detector waveguide 214 and a second auxiliary detector waveguide 216.

[0092] The first auxiliary detector waveguide 214 carries a first portion of the second composite signal to a first auxiliary optical sensor 218 that converts the first portion of the second composite signal into a first auxiliary electrical signal. The second auxiliary detector waveguide 216 carries a second portion of the second composite signal to a second auxiliary optical sensor 220 that converts the second portion of the second composite signal into a second auxiliary electrical signal. Examples of suitable optical sensors include germanium photodiodes (PDs) and avalanche photodiodes (APDs).

[0093] The first optical coupling component 211 couples the first portion of the comparison signal and the first portion of the reference signal into a first composite signal. Due to the frequency difference between the first portion of the comparison signal and the first portion of the reference signal, the first composite signal ripples between the first portion of the comparison signal and the first portion of the reference signal. The optical coupling component 211 also splits the first composite signal into a first detector waveguide 221 and a second detector waveguide 222.

[0094] The first detector waveguide 221 conveys the first portion of the first composite signal to the first optical sensor 223 that converts the first portion of the second composite signal into a first electrical signal. The second detector waveguide 222 conveys the second portion of the second composite signal to the second auxiliary optical sensor 224 that converts the second portion of the second composite signal into a second electrical signal. Examples of suitable optical sensors include germanium photodiodes (PDs), avalanche photodiodes (APDs).

[0095] The first reference waveguide 210 and the second reference waveguide 208 are configured to provide a phase shift between the first portion of the reference signal and the second portion of the reference signal. For example, the first reference waveguide 210 and the second reference waveguide 208 can be configured to provide a 90-degree phase shift between the first portion of the reference signal and the second portion of the reference signal. As an example, one reference signal portion can be an in-phase component and the other a quadrature phase component. Thus, one of the reference signal portions can be a sine function and the other reference signal portion can be a cosine function. In one example, the first reference waveguide 210 and the second reference waveguide 208 are configured such that the first reference signal portion is a cosine function and the second reference signal portion is a sine function. Thus, the reference signal portion of the second composite signal is phase-shifted with respect to the reference signal portion of the first composite signal, while the comparison signal portion of the first composite signal is not phase-shifted with respect to the comparison signal portion of the second composite signal.

[0096] The first optical sensor 223 and the second optical sensor 224 can be connected as a balanced detector, and the first auxiliary optical sensor 218 and the second auxiliary optical sensor 220 can also be connected as a balanced detector. For example, FIG. 4B provides a schematic of the relationship between the electronic circuit, the first optical sensor 223, the second optical sensor 224, the first auxiliary optical sensor 218, and the second auxiliary optical sensor 220. The symbol for a photodiode is used to represent the first optical sensor 223, the second optical sensor 224, the first auxiliary optical sensor 218, and the second auxiliary optical sensor 220, but one or more of these sensors can have other configurations. In some examples, the LIDAR system has all of the components shown in the schematic of FIG. 4B. In some examples, the components shown in the schematic of FIG. 4B are distributed between the LIDAR system and an electronic circuit located remotely from the LIDAR system.

[0097] The electronic circuit connects the first optical sensor 223 and the second optical sensor 224 as a first balanced detector, and the first auxiliary optical sensor 218 and the second auxiliary optical sensor 220 as a second balanced detector. In particular, the first optical sensor 223 and the second optical sensor 224 are connected in series. Additionally, the first auxiliary optical sensor 218 and the second auxiliary optical sensor 220 are connected in series. The series connection of the first balanced detector communicates with a first data line 228 that carries the output from the first balanced detector as a first data signal. The series connection of the second balanced detector communicates with a second data line 232 that carries the output from the first balanced detector as a second data signal. The first data signal and the second data signal are oscillating as a result of the beat between the comparison signal and the reference signal, i.e., the beat of the first composite signal and the second composite signal.

[0098] The first data line 228 conveys a first data signal to the first switch 234. The first switch can be in a first configuration in which the first data signal is conveyed to the distance branch 236, or in a second configuration in which the first data signal is conveyed to the velocity branch 238. In FIG. 4B, the first switch 234 is shown in the first configuration. The second data line 232 conveys a second data signal to the second switch 240. The second switch can be in a first configuration in which the second data signal is conveyed to the distance branch 236, or in a second configuration in which the second data signal is conveyed to the velocity branch 238. In FIG. 4B, the second switch 240 is shown in the first configuration. Suitable switches for use as the first switch and / or the second switch include, but are not limited to, electromechanical switches, and solid state MOSFETs, or PIN diode switches.

[0099] The electronic circuit operates the first switch and the second switch, and during a first period and a second period, they are in the same configuration. For example, the electronic circuit operates the first switch and the second switch such that both the first switch and the second switch are in the first configuration during the first period, and both are in the second configuration during the second period. In this example, the first data signal and the second data signal are conveyed to the distance branch 236 during the first period, and to the velocity branch 238 during the second period.

[0100] During operation of the LIDAR system, the generation of LIDAR data is divided into a series of cycles in which LIDAR data is generated for each cycle. In some examples, each cycle corresponds to a different sample region of the field of view. Thus, different cycles can generate LIDAR data for different regions within the field of view.

[0101] The cycles can be executed such that the time of each cycle can be divided into different time periods such as a first period and a second period. In some examples, the distance between the reflective object and the LIDAR chip can be determined in the first period, and the radial velocity between the reflective object and the LIDAR chip can be determined in the second period.

[0102] The electronic circuit is configured to use a first data signal and a second data signal to determine or approximate the distance between the LIDAR system and the reflective object. For example, during the first period, the electronic circuit can operate the modulator 114 to add a chirp to the amplitude of the emitted LIDAR signal, and thus to the amplitude of the LIDAR output signal. Adding a chirp to the amplitude can include modulating the amplitude of the emitted LIDAR signal such that the amplitude of the emitted LIDAR signal is a function of a sine wave. In one example, the amplitude of the emitted LIDAR signal is modulated such that the amplitude of the output LIDAR signal is a square root of a function that includes a sine wave and / or a square root of a sine wave. For example, the emitted LIDAR signal is modulated according to Equation 1: JPEG0007698098000001.jpg10147, where M, N, C, D, and F are constants, t represents time, and the modulated emitted LIDAR signal and the LIDAR output signal are mathematically represented by M>0, N>0, and M≧N such that the power is not negative, C>0, D≠0. As will be apparent below, F may be a function of the frequency of the LIDAR output signal (f c ). In Equation 1, F and C can be selected such that F>>C.

[0103] The distance branch has a first distance branch line 242. During a first period, the first distance branch line 242 conveys a first data signal to a first multiplier 244. In FIG. 4B, the first multiplier 244 is configured to square the amplitude of the first data signal and output a first multiplied data signal. The distance branch has a second distance branch line 246. During the first period, the second distance branch line 246 conveys a second data signal to a second multiplier 248. In FIG. 4B, the second multiplier 248 is configured to square the amplitude of the second data signal and output a second multiplied data signal. Suitable first and / or second multipliers include, but are not limited to, RF mixers such as Gilbert cell mixers.

[0104] The distance branch has an adder 250 that adds the first multiplied data signal and the second multiplied data signal. The adder outputs an added data signal. Suitable adders include, but are not limited to, resistors or RF couplers including hybrid couplers. The distance branch has a low-pass filter 252 that receives the added data signal and outputs a chirp data signal. The low-pass filter is selected to remove higher frequency contributions to the added data signal that are artifacts of the mixing of the reference signal and the return signal. The low-pass filter can be selected to have a bandwidth of f dmax / 2 + ατ 0max above. Here, f dmax represents the maximum level of the Doppler shift of the LIDAR input signal with respect to the LIDAR input signal for which the LIDAR system will provide reliable results, τ 0max represents the maximum delay between the transmission of the LIDAR output signal and the reception of the LIDAR input signal, and α represents the rate of change of the frequency of the chirp added to the amplitude of the modulated outgoing LIDAR signal during the duration of the sample period (i.e., the first period). In some examples, α is determined from B / T. Here, B represents the change in the frequency of the chirp added to the amplitude of the modulated outgoing LIDAR signal during the duration of the sample period, and T represents the duration of the sample period. In some examples, T is T = [λ c / (2Δv min )]+τ 0max is determined from. Here, λ c represents the wavelength of the emitted LIDAT signal, Δv min represents the velocity resolution, and B can be determined from B = cT / (2(T - τ 0max )ΔR min ). Here, c represents the speed of light, and ΔR min represents the range resolution. In some examples, the filter has a bandwidth greater than 0.1 GHz, 0.2 GHz, or 0.3 GHz and / or less than 0.4 GHz, 0.5 GHz, or 1 GHz. The corresponding values of the sweep period T can be 110 μs, 8 μs, 4 μs, 3 μs, 2 μs, and 1 μs.

[0105] The range branch has an analog-to-digital converter (ADC) 254 that receives the chirped data signal. The analog-to-digital converter (ADC) 254 converts the chirped data signal from analog form to digital form and outputs the result as a digital LIDAR data signal. As described above, the conversion of the chirped data signal includes sampling the chirped data signal at a sampling rate. By adding a chirp to the amplitude of the LIDAR output signal, the influence of the radial velocity is substantially reduced or removed from the composite signal and the resulting electrical signal chirp. For example, the high-frequency shift of the LIDAR output signal (the "frequency shift" Δf) associated with the LIDAR input signal can be described as Δf = Δf d +Δf s . Here, Δf d represents the change in frequency due to the Doppler shift, and Δf s is the change in frequency due to the separation between the reflecting object and the LIDAR system. The emitted LIDAR signal can be modulated to generate a modulated output LIDAR signal, and thus a modulated LIDAR output signal. Here, the change in frequency due to the Doppler shift (Δf d) functions as a LIDAR and is less than 10%, 5%, 1%, or 0.1% of the Doppler shift resulting from a sine wave LIDAR output signal having a constant amplitude and the same frequency as the modulated emitted LIDAR signal and / or the LIDAR output signal. For example, the emitted LIDAR signal and / or the LIDAR output signal can be modulated to generate a modulated output LIDAR signal and / or the LIDAR output signal. Here, the change in frequency due to the Doppler shift (Δf d ) functions as a LIDAR output signal and is less than 10%, 5%, 1%, or 0.1% of the Doppler shift resulting from a continuous wave LIDAR output signal having the same frequency as the modulated emitted LIDAR signal and / or the LIDAR output signal. In another example, the emitted LIDAR signal and / or the LIDAR output signal can be modulated to generate a modulated output LIDAR signal and / or the LIDAR output signal. Here, here, the change in frequency due to the Doppler shift (Δf d ) is less than 10%, 5%, 1%, or 0.1% of the Doppler shift resulting from the unmodulated emitted LIDAR output signal (the unmodulated emitted LIDAT signal) that functions as the LIDAR output signal. These results can be achieved by increasing the value of the variable F with respect to C in Equation 1. For example, F can represent 2πf c , and C can represent 2πf1. Here, f1 indicates the base frequency of the frequency chirp at the amplitude of the modulated output LIDAR signal. Therefore, by increasing the value of the frequency (f c ) of the LIDAR output signal with respect to the chirp base frequency (f1), F can be increased with respect to C. As an example, f c and f1 can be selected such that f c >> f1. In some examples, the ratio of f c :f1 is greater than 2:1, 10:1, 1×10 4 :1, 5×10 4 , or 1×10 5 :1, and / or greater than 5×10 5 , 1×10 6 , 5×10 6 , or 5×10 8such that f is made smaller c , and f1 are selected. Thus, the variables F and C can have these same values with respect to the ratio F:C. By reducing and / or removing the change in frequency (Δf d ) due to Doppler shift from the frequency shift, the ringing frequency is reduced and thus the required sampling rate is decreased.

[0106] The range branch has a conversion module 256 that receives a digital LIDAR data signal from an analog-to-digital converter (ADC) 254. The conversion module 256 is configured to perform an actual conversion on the digital LIDAR data signal so as to convert from the time domain to the frequency domain. This conversion provides a clear solution for the shift in the frequency of the LIDAR input signal with respect to the shift in the LIDAR input signal caused by the distance between the reflecting object and the LIDAR system. A suitable actual conversion is a Fourier transform such as a fast Fourier transform (FFT). The classification of a conversion such as an actual conversion distinguishes that conversion from a complex conversion such as a complex Fourier transform. The conversion module can perform the attributed functions using firmware, hardware, software, or a combination thereof.

[0107] Since the frequency provided by the conversion module has no input, or substantially no input, from the frequency shift due to relative movement, the determined frequency shift can be utilized to approximate the distance between the reflecting object and the LIDAR system. For example, an electronic circuit can use Equation 3: JPEG0007698098000002.jpg964 to approximate the distance between the reflecting object and the LIDAR system (R0). Here, Δf can be approximated as the peak frequency output from the conversion module, and c is the speed of light.

[0108] Velocity divergence can be configured to use a first data signal and a second data signal to determine, or approximate, at least the radial velocity of a LIDAR system and a reflecting object. A LIDAR output signal having a frequency that is a function of time, as disclosed in the context of FIGS. 1A through 2, can be replaced by a LIDAR output signal whose frequency is not a function of time. For example, the LIDAR output signal can be a continuous wave (CW). For example, during a second period, the emitted LIDAR signal that is modulated, and thus the LIDAR output signal, can be an unchirped continuous wave (CW). As an example, the modulated emitted LIDAR signal, and thus the LIDAR output signal, can be represented by Equation 2: It can be represented by JPEG0007698098000003.jpg1054. Here, G and H are constants, and t represents time. In some examples, G represents the square root of the power of the emitted LIDAR signal, and / or H represents the constant F from Equation 1. If the output of the light source has the waveform required for the modulated output LIDAR signal, the electronic circuit does not need to operate the modulator 114 to modify the emitted LIDAR signal. In these examples, the output of the light source can function as the modulated output LIDAR signal, and thus the LIDAR output signal. In some examples, the electronic circuit operates the modulator 114 to generate the modulated emitted LIDAR signal in a desired form.

[0109] Since the frequency of the LIDAR output signal is constant during the second period, a change in the distance between the reflecting object and the LIDAR system does not cause a change in the frequency of the LIDAR input signal. As a result, the separation distance does not contribute to the frequency shift of the LIDAR input signal relative to the frequency of the LIDAR output signal. Thus, the influence of the separation distance is removed, or substantially removed, from the frequency shift of the LIDAR input signal relative to the frequency of the LIDAR output signal.

[0110] The speed bifurcation has a first speed bifurcation line 260 and a second speed bifurcation line 260. During the second period, the first speed bifurcation line 260 conveys a first data signal to an analog-to-digital converter (ADC) 264 that converts the first data signal from analog form to digital form and outputs a first digital data signal. As described above, the conversion of the first data signal is performed by sampling the first data signal at a sampling rate. The use of a continuous wave as the LIDAR output signal substantially removes the influence of the distance between the reflecting object and the LIDAR system and the resulting electrical signal from the chirp of the composite signal. Accordingly, the chirp frequency is reduced and the required sampling rate is reduced.

[0111] The second speed bifurcation line 262 conveys a second data signal to an analog-to-digital converter (ADC) 266 that converts the second data signal from analog form to digital form and outputs a second digital data signal. As described above, the conversion of the second data signal is performed by sampling the second data signal at a sampling rate. The use of a continuous wave as the LIDAR output signal substantially removes the influence of the distance between the reflecting object and the LIDAR system and the resulting electrical signal from the chirp of the second composite signal. Accordingly, the chirp frequency is reduced and the required sampling rate is reduced.

[0112] The sampling rate of the analog-to-digital converter (ADC) 264 may be the same as or different from the sampling rate of the analog-to-digital converter (ADC) 266.

[0113] The velocity branch has a conversion module 268 that receives a first digital data signal from an analog-to-digital converter (ADC) 264 and a second digital data signal from an analog-to-digital converter (ADC) 266. Since the first data signal is the in-phase component and the second data signal is its quadrature component, both the first data signal and the second data signal act as a complex velocity data signal where the first data signal is the real component and the second data signal is the imaginary component. As a result, the first digital data signal can be the real component of the digital velocity data signal, and the second data signal can be the imaginary component of the digital velocity data signal. The conversion module 168 can be configured to perform a complex conversion on the digital velocity data signal, converting it from the time domain to the frequency domain. This conversion provides a clear solution regarding the frequency shift of the LIDAR input signal caused by the radial velocity between the reflecting object and the LIDAR system. A suitable complex conversion is a Fourier transform such as a complex fast Fourier transform (FFT). The conversion module can perform the attributed functions using firmware, hardware, software, or a combination thereof.

[0114] Since the frequency shift provided by the conversion module 268 has no input from the frequency shift due to the separation distance between the reflecting object and the LIDAR system, and due to the complex nature of the velocity data signal, the output of the conversion module 268 can be used to approximate the radial velocity between the reflecting object and the LIDAR system. For example, an electronic circuit can use Equation 4: v = c * f d / (2 * f c ) to approximate the radial velocity (v) between the reflecting object and the LIDAR system. Here, f d is approximated as the peak frequency output from the conversion module 268, c is the speed of light, and f c represents the frequency of the LIDAR output signal.

[0115] Additional components can be added to the schematic of FIG. 4B. For example, if the LIDAR system generates multiple LIDAR output signals or is used with another LIDAR system that generates LIDAR output signals (i.e., by frequency or wavelength division multiplexing, FDM / WDM), the LIDAR system can have one or more filters for removing interference signals from the chirp data signal and / or the real and / or imaginary components of the velocity data signal. Thus, the LIDAR system can have one or more filters in addition to the illustrated components. Suitable filters include, but are not limited to, low-pass filters. In the case of optical design, additional filtering may not be required as the frequency of the interference component is effectively provided by the balanced detector when it is outside the bandwidth of the balanced detector.

[0116] The sampling rate used between the first period and the second period can be selected to have a value greater than or equal to the larger of two values selected from the group consisting of the minimum sampling rate of the first period and the minimum sampling rate of the second period. For example, during the first period, the range of the rate of the first period sampling rate (f s1 ) can be determined by f s1 ≧2×ατ 0max where τ 0max represents the maximum amount of time between the transmission of the LIDAR output signal and the reception of the LIDAR input signal. During the second period, the range of the rate of the second period sampling rate (f s2 ) can be determined by f s2 ≧2×f dmax where f dmaxrepresents the maximum level of the Doppler shift of the LIDAR input signal with respect to the LIDAR input signal for the LIDAR system to provide reliable results. The maximum value is determined by the maximum level at which the LIDAR system provides reliable results. Thus, the maximum distance generally corresponds to the distance of the field of view set in the LIDAR specifications, and the maximum Doppler shift generally corresponds to the Doppler shift that occurs at the maximum radial velocity value set in those specifications. These two equations show that the minimum sampling rate for the first period is 2ατ 0max and the minimum sampling rate for the second period is 2f dmax . As a result, the sampling rate is selected to have a value greater than or equal to the larger of the values of 2ατ 0max and 2f dmax . The sample rate (fs) used between the first period and the second period is f s ≧max(2ατ 0max , 2f dmax ). In some examples, the sample rate (f s ) used between the first period and the second period is 0.1 GHz, 0.2 GHz, or 0.5 GHz or more, and / or less than 1 GHz, 2 GHz, or 4 GHz.

[0117] The above description of the operation of the LIDAR system assumes that the modulator is present in the utility waveguide 112. However, the modulator is optional. In these examples, the electronic circuit can operate the light source 110 to increase the frequency of the emitted LIDAR signal during the first period and decrease the frequency of the emitted LIDAR signal during the second period. An appropriate method for extracting LIDAR data from the resulting composite signal is disclosed in U.S. Patent Application No. 62 / 671,913, filed on May 15, 2018, entitled "Optical Sensor Chip", the entire disclosure of which is incorporated herein by reference.

[0118] The LIDAR systems of FIGS. 3 to 4B are disclosed as generating a transmission signal having a plurality of channels, but the LIDAR systems of FIGS. 3 to 4B can be configured to generate a transmission signal having a single channel. Accordingly, the light source can be configured to output a single channel.

[0119] The light source of FIGS. 1 to 4B is illustrated as a single component, but the light source can be composed of a plurality of components. For example, the light source can have a plurality of different lasers that generate laser outputs multiplexed together to generate a LIDAR output signal.

[0120] FIG. 5 shows a schematic diagram of an optical manifold system suitable for use with the above LIDAR system. The optical manifold system has a housing 300 having one or more cores 302. Each core can be configured according to the LIDAR system of FIGS. 1 to 2 or FIGS. 3 to 4B, or each core can have a different configuration. Each core has a LIDAR waveguide 304 that can be the utility waveguide 16 of FIG. 1 or the LIDAR signal waveguide 124 of FIG. 3. As a result, the LIDAR waveguide 304 can output an output LIDAR signal and receive an incident LIDAR signal. In addition, the outgoing LIDAR signal and the outgoing LIDAR signal can each have one or more channels.

[0121] Each core has an interface 306 between a LIDAR waveguide 304 and an optical interconnect 308 such as an optical fiber. The optical interconnect can carry the outgoing LIDAR signal to the connector 310 and can carry the incoming LIDAR signal from the connector 310 to the interface 306. The optical interconnect is optional, and the interface can be between the LIDAR waveguide 304 and the connector 310. Suitable interfaces include, but are not limited to, lenses that couple to polished or etched waveguide facets, fiber block assemblies coupled to polished or etched facet waveguide facets, and mirrors or grating couplers coupled to lenses or fiber block assemblies. Suitable connectors include, but are not limited to, ferrule connectors such as FC, LC, MPO / MPT.

[0122] The core is associated with core electronics 312 that operate each core and generate LIDAR data from the associated cores as disclosed in the context of FIGS. 1 - 4. Thus, the core electronics can be the electronics disclosed in the context of FIGS. 1 - 2 or the electronics disclosed in the context of FIGS. 3 - 4. Each core and the associated core electronics can optionally be included on a single core card 316. Suitable core cards include, but are not limited to, printed circuit boards (PCBs).

[0123] The electrical link 318 provides electrical communication between each core and the connector 310. Suitable electrical links 318 include, but are not limited to, coaxial cables and twisted pair cables.

[0124] Each of the data electrical links 320 provides electrical communication between one of the cores and the master electronic circuit 322. In some examples, the master electronic circuit is included in a master board 324, such as a printed circuit board (PCB). When the master electronic circuit is included in the master board 324, the core and the core electronic circuit 312 can be implemented on the master board 324. For example, when the core and the associated core electronic circuit are on a core card 316, the core cards 316 can be implemented on the master board 324, respectively.

[0125] The control electrical link 325 provides electrical communication between the master electronic circuit 322 and the remote electronic circuit 326. In addition to processing signals from the master electronic circuit 322, the remote electronic circuit 326 generally processes signals from various different sensors. For example, when an optical manifold is included in a vehicle, the remote electronic circuit 326 can process signals from cameras, inertial sensors, rotational sensors, radar, infrared (IR) cameras, wireless navigation systems such as a global positioning system (GPS), and acoustic sensors such as microphones.

[0126] Each of the communication links 328 provides electrical communication between one of the connectors 310 and the scanning head 330. The communication links are each configured to carry the outgoing LIDAR signal from the connector 310 to the scanning head 330 and to carry the incoming LIDAR signal from the scanning head 330 to the connector 310. Thus, the communication links enable electrical communication between the core electronic circuit and the scanning head associated therewith. It is configured to provide electricity. When the communication link 328 carries both optical and electrical signals, the communication link can include waveguides such as optical fibers and conductors such as wires and cables.

[0127] During operation of the optical manifold, each core electronic circuit operates its associated core as disclosed in the context of FIGS. 1 through 4B. Thus, each core electronic circuit generates LIDAR data for different sample regions of the field of view. The core electronic circuit can provide the generated LIDAR data to the master electronic circuit via the data electrical link 320. The master electronic circuit can provide the generated LIDAR data to the remote electronic circuit via the communication link 329. Thus, the remote electronic circuit can receive one or more electrical signals having a series of data fields from the optical manifold including a data stream. The data fields can be arranged and the LIDAR data associated with the identified sample regions with respect to the sample regions of the field of view and a series of different sample regions can be identified. In some examples, the remote electronic circuit combines the received LIDAR data with data from other sources such as cameras, inertial sensors, rotational sensors, radar, infrared (IR) cameras, wireless navigation systems such as global positioning system (GPS), and acoustic sensors such as microphones. The remote electronic circuit can combine the LIDAR data and other data to control the device.

[0128] The connector is shown as a single connector, but each connector can have one or more connectors. For example, one of the illustrated connectors can have one or more optical connectors that provide an interface between optical components such as between a waveguide such as an optical fiber and one or more electrical connectors that provide an interface between electrical components such as wires, cables, conductive lines, and conductors such as metal traces.

[0129] By using the connector, the core can be easily replaced and the manifold can be reconfigured. For example, the interior of the housing 300 is accessible by an operator. As an example, the housing can have one or more covers and / or one or more lids that allow the operator to access the interior of the housing. An example of a suitable cover includes, but is not limited to, a PC expansion slot cover. As a result, the operator can disconnect the first core card 316 from the associated connector and subsequently connect the second core card 316 to the connector to replace the first core card 316 disposed in the manifold with the second core card 316. The first core card 316 can have optical characteristics different from those of the second core card 316. For example, the first core card 316 can generate an emitted LIDAR signal different from that of the second core card. As an example, the emitted LIDAR signal generated by the first core card 316 and the emitted LIDAR signal generated by the second core card 316 can have one or more different characteristics selected from the group consisting of a different number of channels, different channel wavelengths, different channel modulation / chirp configurations, and different coherent receiver configurations. Other optical characteristics that can be different between the first core card 316 and the second core card include, but are not limited to, the presence or absence of means for amplification, the presence or absence of additional optical components such as multiplexers, demultiplexers, and splitters. In addition to or instead of having optical characteristics different from those of the second core card 316, the core electronic circuit of the first core card can be made different from the core electronic circuit of the second core card. As an example, the core electronic circuit of the first core card can generate LIDAR data as disclosed in the context of FIGS. 1 and 2, and the second core card can generate LIDAR data as disclosed in the context of FIGS. 3 and 4. Other electrical characteristics that can be different between the first core card 316 and the second core card include, but are not limited to, sampling speed capability, digital bit resolution, and signal processing capability. The ability to exchange core cards enables the modification of the characteristics of the manifold by changing the core of the housing.

[0130] The manifold of FIG. 5 shows each core and / or each core card that generates a single LIDAR output signal, but one or more cores can be configured to generate multiple LIDAR output signals. LIDAR output signals from the same core can be received by different scanning heads. As a result, a single core and / or core card can be associated with one or more scanning heads.

[0131] FIG. 6 shows one application example of the illustrated optical manifold system. The optical manifold system is included in a transport vehicle such as an automobile. The scanning heads 330 are arranged at various different positions around the vehicle. The housing is arranged in a safe place such as a trunk. The master electronic circuit of the housing communicates electrically with a remote electronic circuit also arranged in the trunk. In this configuration, LIDAR data can be generated for a plurality of different fields of view arranged around the vehicle, and the remote electronic circuit can combine the LIDAR data with data generated from other sensors and devices.

[0132] FIGS. 7A and 7B show a suitable configuration of a scanning head or a part of a scanning head. The scanning head has a head waveguide 350 that receives an emitted LIDAR signal via a communication link 328. The head waveguide 350 conveys the emitted LIDAR signal to a splitter 352 that splits the emitted LIDAR signal into a plurality of output signals that are each conveyed to a different steering waveguide 354. Each steering waveguide terminates at a facet 356. The facets are arranged such that output signals exiting the chip through the facets combine to form an output signal. LIDAR

[0133] ​​During operation of the scanning head, at least a portion of the output signal is reflected by an object remote from the chip. At least a portion of the reflected signal returns to the facet 356 of the steering waveguide 354 and also enters the steering waveguide 354 as part of the LIDAR input signal. The steering waveguide 354 conveys a portion of the LIDAR input signal to the splitter 354 where they are combined with the incident LIDAR signal conveyed in the head waveguide 350.

[0134] The splitter 352 and the steering waveguide 354 can be configured such that there is a phase difference between the output signals at the facets 356 of adjacent steering waveguides 354. For example, the splitter 352 and the steering waveguide 354 can be configured such that there is a linearly increasing phase difference between the output signals at the facets 356 of adjacent steering waveguides 354. For example, the steering waveguide 354 can be configured such that the phase of the steering waveguide numbered j is f0+(j - 1)f. Here, j is an integer from 1 to N, and when the steering waveguides are consecutively numbered as shown in FIGS. 7A and 7B, it represents the number associated with the steering waveguide, f is the phase difference between adjacent steering waveguides, and f0 is the phase of the output signal at the facet 356 of the steering waveguide j = 1. In some examples, the phase difference is achieved by configuring the steering waveguide such that the steering waveguide has a difference in length that linearly increases. For example, the length of the steering waveguide j can be represented by L0+(j - 1)ΔL. Here, j is an integer from 1 to N, and when the steering waveguides are consecutively numbered as shown in FIGS. 7A and 7B, it represents the number associated with the steering waveguide, ΔL is the difference in length between adjacent steering waveguides, and L0 is the length of the steering waveguide j = 1. Suitable ΔL includes, but is not limited to, ΔL greater than 0 or 5 μm and / or less than 25 or 50 μm. Suitable f includes, but is not limited to, f greater than 0π or 7π and / or less than 15π or 20π. Suitable N includes, but is not limited to, N greater than 10 or 500 and / or less than 1000 or 2000. Suitable splitters include, but are not limited to, star couplers, cascaded Y-junctions, and cascaded 1×2 MMI couplers. The configuration of the steering waveguide 354 in FIG. 7B is preferred as the difference in length between adjacent steering waveguides (ΔL) increases.

[0135] When the output LIDAR signal has a plurality of different channels, the length difference (ΔL) between adjacent steering waveguides is a different percentage of the wavelengths of the different channels. As a result, the output signal is separated into a plurality of different LIDAR output signals that each travel away from the scanning head in a different direction (θ). Each of the different LIDAR output signals is associated with a different channel. Thus, the scanning head outputs one or more LIDAR output signals each associated with a different channel.

[0136] When the steering waveguides are of the same length, the value of ΔL is zero, and the value of f is zero. Suitable ΔL includes, but is not limited to, ΔL that is 0 or greater than 5 μm and / or less than 10 or 15 μm. Suitable f includes, but is not limited to, f that is 0π or greater than 7π and / or less than 15π or 20π. Suitable N includes, but is not limited to, N that is greater than 10 or 500 and / or less than 1000 or 2000. Suitable splitters 352 include, but are not limited to, star couplers, cascaded Y-junctions, and cascaded 1×2 MMI couplers.

[0137] The electronic circuit of the optical manifold system can change one or more characteristics of the emitted LIDAR signal and change the direction in which one or more LIDAR output signals travel away from the scanning head. For example, the core electronic circuit can adjust the wavelength and / or frequency of one or more channels of the output LIDAR signal and change the direction in which one or more LIDAR output signals travel away from the scanning head. Thus, the electronic circuit of the optical manifold system can adjust the direction of one or more LIDAR output signals and scan the LIDAR output signals to different sample regions of the field of view.

[0138] If the adjustment provided by the electronic circuit of the optical manifold system is sufficient, the chip configured according to FIG. 7A and / or FIG. 7B can function as a scanning head. In these examples, the communication link need not have a conductor. However, when the field of view is two-dimensional, it is desirable to be able to scan in both the vertical and horizontal directions.

[0139] The above head structure is suitable for use with various scanning mechanisms used in LIDAR applications. For example, the output signal can be received by one or more reflecting devices and / or one or more collimating devices. One or more reflecting devices can be configured to redirect and / or steer the LIDAR output signal so as to provide scanning of the LIDAR output signal. Suitable reflecting devices include, but are not limited to, mechanically driven mirrors and microelectromechanical system (MEMS) mirrors. One or more collimating devices provide collimation of the LIDAR output signal and thus can increase the portion of the LIDAR input signal received by the scanning head. Suitable collimating devices include, but are not limited to, individual lenses and compound lenses.

[0140] FIG. 8 shows the above-described scanning head used with a reflecting device 400 and a collimating device 402. For example, the lens functions as a collimating device that receives the LIDAR output signal and provides collimation of the LIDAR output signal. The mirror functions as a reflecting device 400 that receives the collimated LIDAR output signal and reflects the collimated LIDAR output signal in a desired direction. As indicated by the arrow labeled A, the core electronic circuit can move the mirror so as to steer and / or scan the collimated LIDAR output signal. The movement of the mirror can be two-dimensional or three-dimensional. Suitable mirrors include, but are not limited to, mechanically driven mirrors and microelectromechanical system (MEMS) mirrors.

[0141] FIG. 9 shows the above-described scanning head used with the reflecting device 400 and the collimating device 402. For example, the mirror functions as a reflecting device 400 that receives the LIDAR output signal and reflects the LIDAR output signal in a desired direction. As indicated by the arrow labeled A, the core electronic circuit can move the mirror so as to steer and / or scan the LIDAR output signal. The lens functions as a collimating device 402 that receives the LIDAR output signal from the mirror and provides collimation of the LIDAR output signal. The lens can be configured to move with the movement of the mirror so that the lens continues to receive the LIDAR output signal at different positions of the mirror. Alternatively, the movement of the mirror can be sufficiently restricted so that the lens continues to receive the LIDAR output signal at different positions of the mirror. The movement of the mirror can be two-dimensional or three-dimensional. Suitable mirrors include, but are not limited to, mechanically driven mirrors and microelectromechanical system (MEMS) mirrors.

[0142] Techniques such as SOI MEMS (Silicon-On-Insulator Micro Electro Mechanical System) technology can be used to directly integrate a reflecting device such as a MEMS mirror onto a chip. For example, the scanning head of FIG. 7 can be constructed on an optical platform such as a silicon-on-insulator wafer and the MEMS mirror can be directly integrated into the scanning head.

[0143] Adopt other beam steering mechanisms to steer the LIDAR output signals in the field of view. An example of the beam steering mechanism is disclosed in FIGS. 10A and 10B. FIG. 10A is a side view of the steering mechanism, and FIG. 10B is a plan view of the steering mechanism. The scanning head 500 in FIG. 7 is held by a holder 502 disposed on a stage 504. The line labeled x in FIG. 10A indicates the movement of the scanning head 500 relative to the stage, and the line labeled z in FIG. 10B indicates the movement of the scanning head 500 relative to the stage. The movement in FIG. 10A is in a first plane, and the movement in FIG. 10B is in a second plane perpendicular to the first plane. The core electronic circuit can use one or both of the operations to steer the LIDAR output signal from one sample area to the next sample area.

[0144] FIGS. 10A and 10B show the translational movement of the scanning head. However, rotational movement is also possible. For example, the line labeled Rz in FIG. 10C represents the rotation of the stage and / or the scanning head that provides the movement of each LIDAR output signal in the first plane. The line labeled R in FIG. 10D represents the rotation of the stage and / or the scanning head that provides the movement of each LIDAR output signal in a second plane perpendicular to one or more first planes. The core electronic circuit can use one or both of these rotational movements to steer the LIDAR output signal from one sample area to the next sample area. Therefore, the core electronic circuit can use one or more translational movements and / or one or more rotational movements to steer the LIDAR output signal from one sample area to the next sample area.

[0145] The translational motion can be provided by an actuator (not shown), such as a linear motion stage, like the piezoelectric motor-driven stage Q-552.030 (PI USA, 2018) having a speed of 10 mm / s and a maximum linear travel range of 6.5 mm. The rotational motion can be provided by an actuator, such as the Q622930 Q-Motion miniature rotary stage (PI USA, 2018). The core electronic circuit can control the translational and / or rotational actuator by an electrical signal supplied to the scanning head via the communication link 328.

[0146] Suitable electronic circuits for use as each of the different electronic circuits (core electronic circuit, master electronic circuit, and remote electronic circuit) can include, but are not limited to, analog electrical circuits, digital electrical circuits, processors, microprocessors, digital signal processors (DSPs), field programmable gate arrays (FPGAs), computers, microcomputers, or control devices having or configured with a suitable combination to perform, monitor, and control the functions described above. In some examples, the control device accesses a memory having instructions executed by the control device during the performance of the operation, control, and monitoring functions. Although the electronic circuit is shown as a single component in a single location, the electronic circuit can have a plurality of different components that are independent of each other and / or located in different locations. Further, as described above, all or a portion of the disclosed electronic circuits can be provided on a chip having an electronic circuit integrated with the chip.

[0147] Other embodiments, combinations, and modifications of the present invention will be readily apparent to those skilled in the art in view of these teachings. Accordingly, the present invention should be limited only by the following claims, which include all such embodiments and modifications when viewed in connection with the above specification. <<< List of Term Symbols >>> 8 Component assembly 10 Light source 12 Cavity waveguide 13 Recess 14 Partial return device 15 Partial reflection device 15 Reflection device 16 Utility waveguide 18 Facet 24 Data branch 26 Optical coupler 27 Reference waveguide 28 Optical coupling component 30 Comparison waveguide 36 Detector waveguide 38 Detector waveguide 40 Optical sensor 42 Optical sensor 44 Data optical attenuator 46 Output optical attenuator 46 Optical attenuator 50 Sampling directional coupler 52 Sampling waveguide 54 Sampling optical sensor 55 Control branch 56 Directional coupler 57 Control waveguide 58 Interferometer 60 Interferometer waveguide 61 Control optical sensor 62 Electronic circuit 80 Embedded layer 82 Substrate 84 Optical transmission medium 86 Ridge 88 Slab region 110 Light source 112 Utility waveguide 114 Modulator 116 Amplifier 118 Signal directing component 118 Facet 120 LIDAR branch 122 Data branch 124 LIDAR signal waveguide 128 Comparison signal waveguide 130 Comparison demultiplexer 132 Comparison waveguide 134 Processing component 136 Reference signal waveguide 138 Reference demultiplexer 140 Reference waveguide 142 Optical amplifier 168 Conversion module 200 Splitter 202 Splitter 204 Comparison waveguide 206 Comparison waveguide 208 Reference waveguide 208 Comparison waveguide 210 Reference waveguide 211 Optical coupling component 212 Optical coupling component 214 Auxiliary detector waveguide 216 Auxiliary detector waveguide 218 First auxiliary optical sensor 220 Second auxiliary optical sensor 221 Detector waveguide 222 Detector waveguide 223 Optical sensor 224 Auxiliary optical sensor 224 Optical sensor 225 Balanced detector 226 Balanced detector 228 Data line 232 Data line 234 Switch 236 Distance branch 238 Speed branch 240 Switch 242 Distance branch line 244 Multiplier 246 Distance branch line 248 Multiplier 250 Adder 252 Low-pass filter 256 Conversion module 260 Speed branch line 262 Speed branch line 268 Conversion module 300 Housing 302 Core 304 LIDAR waveguide 306 Interface 308 Optical Interconnection Section 310 Connector 312 Core Electronic Circuit 316 Core Card 318 Electrical Link 320 Data Electrical Link 322 Master Electronic Circuit 324 Master Board 325 Control Electrical Link 326 Remote Electronic Circuit 328 Communication Link 329 Communication Link 330 Scanning Head 350 Head Waveguide 352 Splitter 354 Steering Waveguide 354 Splitter 356 Facet 400 Reflective Device 402 Collimating Device 500 Scanning Head 502 Holder

Claims

1. an optical manifold having a housing in which a plurality of cores are disposed, each core generating an output LIDAR signal carrying one or more channels; scan heads positioned away from the optical manifold and each associated with one of the cores, each scan head configured to receive an outgoing LIDAR signal from its associated core, each scan head configured to transmit one or more LIDAR output signals, each having light from a different one of the channels, and each of the different LIDAR output signals configured to travel in a different direction away from the scan head; the cores are each included in a different core card, one of the core cards being a first core card connected to a first connector of the housing, and the outgoing LIDAR signal generated by the core included in the first core card being a first outgoing LIDAR signal; one of the other core cards is a second core card disposed outside the housing but configured to be connected to the first connector, the second core card having a core configured to generate a second outgoing LIDAR signal carrying one or more second channels, the second outgoing LIDAR signal having different optical characteristics than the first outgoing LIDAR signal; and Actuators each configured to move a different one of the scan heads such that the LIDAR output signal output from the scan head is directed within the field of view of the scan head. having LIDAR system.

2. The difference between the optical properties of the first outgoing LIDAR signal and the second outgoing LIDAR signal is different numbers of channels carried by the first and second outgoing LIDAR signals; different channel wavelengths carried by the first and second outgoing LIDAR signals; different channel waveforms carried by the first and second outgoing LIDAR signals; different modulations of the channels carried by the first and second outgoing LIDAR signals; and chirps of the channels carried by the first and second outgoing LIDAR signals. having at least one difference selected from the group consisting of:

2. The LIDAR system of claim 1.

3. each said core being associated with a different core electronics, and said core electronics being configured to adjust a characteristic of one of said outgoing LIDAR signals, said adjustment of said characteristic causing said one or more LIDAR output signals to change in a direction traveling away from said scan head associated with said core electronics; 2. The LIDAR system of claim 1.

4. Each core electronic circuit is configured to generate LIDAR data from the outgoing LIDAR signal generated by the associated core, the LIDAR data having at least one component selected from the group consisting of: a radial separation between the LIDAR system and an object located outside the LIDAR system, and a radial velocity between the LIDAR system and an object located outside the LIDAR system.

4. The LIDAR system of claim 3.

5. The core included in the second core card is configured to generate LIDAR data from the second outgoing LIDAR signal.

5. The LIDAR system of claim 4.

6. an optical fiber carries the first outgoing LIDAR signal from the optical manifold to one of the scan heads; The system of claim 1 .

7. the first core card is disposed in a housing for the optical manifold; The system of claim 1 .

8. disposing a plurality of cores within a housing for an optical manifold, each core configured to generate an outgoing LIDAR signal carrying one or more channels, each core associated with a scan head disposed remotely from the optical manifold, the scan head configured to receive the outgoing LIDAR signal from the associated core; Each of the actuators is configured to move a different one of the scan heads such that the LIDAR output signals output from the scan heads are directed within a field of view of the scan head; one of the cores is a first core; and Replacing the first core with a second core, the second core is configured to generate a second emitted LIDAR signal carrying one or more second channels, the second emitted LIDAR signal having different optical characteristics than the emitted LIDAR signal generated by the first core; How to operate the optical manifold.

9. The difference between the optical properties of the first outgoing LIDAR signal and the second outgoing LIDAR signal is different numbers of channels carried by the first and second outgoing LIDAR signals; different channel wavelengths carried by the first and second outgoing LIDAR signals; different channel waveforms carried by the first and second outgoing LIDAR signals; different modulations of the channels carried by the first and second outgoing LIDAR signals; and chirps of the channels carried by the first and second outgoing LIDAR signals. having at least one difference selected from the group consisting of: The method according to claim 8.

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