CN114814788A - On-chip polarized light generating device for frequency modulation continuous wave laser radar - Google Patents
On-chip polarized light generating device for frequency modulation continuous wave laser radar Download PDFInfo
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- CN114814788A CN114814788A CN202210738157.9A CN202210738157A CN114814788A CN 114814788 A CN114814788 A CN 114814788A CN 202210738157 A CN202210738157 A CN 202210738157A CN 114814788 A CN114814788 A CN 114814788A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
- G01S17/88—Lidar systems specially adapted for specific applications
- G01S17/93—Lidar systems specially adapted for specific applications for anti-collision purposes
- G01S17/931—Lidar systems specially adapted for specific applications for anti-collision purposes of land vehicles
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
- G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
- G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
- G01S7/481—Constructional features, e.g. arrangements of optical elements
- G01S7/4818—Constructional features, e.g. arrangements of optical elements using optical fibres
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
- G02B27/28—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising
- G02B27/283—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 for polarising used for beam splitting or combining
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- General Physics & Mathematics (AREA)
- Computer Networks & Wireless Communication (AREA)
- Radar, Positioning & Navigation (AREA)
- Remote Sensing (AREA)
- Electromagnetism (AREA)
- Optics & Photonics (AREA)
- Optical Radar Systems And Details Thereof (AREA)
Abstract
The invention provides an on-chip polarized light generating device for a frequency modulation continuous wave laser radar, which comprises: a polarization rotation beam splitting part PSR configured to separate a TE polarized light component and a TM polarized light component in input light to generate a first TE polarized light component and convert the TM polarized light component into a second TE polarized light component; a first phase modulator pair and a second phase modulator pair configured to adjust optical paths of the first TE polarized light component and the second TE polarized light component, respectively; and a beam combiner configured to combine the two adjusted TE polarized light components into one light.
Description
Technical Field
The present disclosure relates generally to lidar, and in particular to frequency modulated continuous wave lidar, and an on-chip polarized light generating apparatus for frequency modulated continuous wave lidar.
Background
Lidar devices are now widely deployed in different scenarios, including autonomous vehicles. The lidar may actively estimate distances to environmental features while scanning the scene to generate a point location cloud indicative of a three-dimensional shape of the environmental scene.
In general, a frequency modulated continuous wave lidar system may be configured to emit light, typically from a laser light source, wherein the frequency of the emitted light may vary over time such that the light frequency variation may appear as a triangle in a time-frequency diagram as shown in fig. 1. The frequency modulated light may include a first half cycle in which the frequency of the light increases with time and a second half cycle in which the frequency of the light decreases with time. The emitted light is emitted and reflected from the surface of the object after a period of time and is received by the lidar system. The frequency variation of the received light can also be represented as a triangle in the time-frequency diagram, since reflection only introduces a time delay and does not change the frequency of the transmitted light. The lidar system may then detect a stable frequency difference between the transmitted light and the received light. The processor of the lidar system may be configured to calculate a distance between the lidar system and the surface of the object according to the following equation:
Where d represents the distance, Δ f represents the frequency difference, c represents the speed of light, and α represents the slope of the change in the frequency of light with time.
Disclosure of Invention
Technical problem
In a conventional fm cw lidar, in order to transmit light from a laser light source to an optical chip of the fm cw lidar system, a polarization maintaining fiber must be used as an optical fiber between the light source and the optical chip. The laser emits Frequency Modulated Continuous Wave (FMCW) which is amplified by a polarization maintaining fiber amplifier, coupled to a laser radar optical chip through a polarization maintaining fiber, and transmitted to an FMCW engine or an OPA antenna array through a 1 to N optical splitter.
However, the polarization maintaining optical fiber is expensive, and the polarization maintaining optical fiber is adopted in the laser radar, so that the overall cost of the laser radar is increased.
Solution scheme
According to an embodiment of the present invention, there is provided an on-chip polarized light generating apparatus for a frequency modulated continuous wave lidar, including: a polarization rotation beam splitting part PSR configured to separate a TE polarized light component and a TM polarized light component in input light to generate a first TE polarized light component and convert the TM polarized light component into a second TE polarized light component; a first phase modulator pair and a second phase modulator pair configured to adjust optical paths of the first TE polarized light component and the second TE polarized light component, respectively; and a beam combiner configured to combine the two adjusted TE polarized light components into one light.
According to an embodiment of the present invention, there is provided an on-chip polarized light generating apparatus for a frequency modulated continuous wave lidar, further including: the monitoring device comprises a monitoring beam splitter and a Monitoring Photoelectric Detector (MPD), wherein the monitoring beam splitter is configured to separate first monitoring light for monitoring from light synthesized by the beam combiner, and provide the first monitoring light to the Monitoring Photoelectric Detector (MPD), and the Monitoring Photoelectric Detector (MPD) is configured to monitor photocurrent of the first monitoring light.
According to an embodiment of the present invention, there is provided an on-chip polarized light generating apparatus for a frequency modulated continuous wave lidar, wherein the first and second phase modulator pairs are adjusted according to a monitoring result of the monitoring photodetector MPD to adjust optical paths of the first and second TE polarized light components.
There is provided an on-chip polarized light generating apparatus for a frequency modulated continuous wave lidar according to an embodiment of the present invention further including a 3dB coupler, the 3dB coupler being disposed between the first phase modulator pair and the second phase modulator pair so that a first TE polarization component and a second TE polarization component after passing through the first phase modulator pair to adjust an optical path constructively interfere.
There is provided in accordance with an embodiment of the present invention an on-chip polarized light generating apparatus for frequency modulated continuous wave lidar wherein the first phase modulator pair comprises a first phase modulator and a second phase modulator and the second phase modulator pair comprises a third phase modulator and a fourth phase modulator, wherein the first phase modulator pair and the second phase modulator pair comprise a III-V material or lithium niobate based phase modulator, a thermal modulator or an electrical modulator.
There is provided, in accordance with an embodiment of the present invention, a frequency modulated continuous wave lidar including an on-chip polarized light generating device, including: a light source; and a silicon optical chip connected with the light source through a non-polarization maintaining fiber, and including: an on-chip polarized light generating device, a beam splitter, a light emitting and receiving device, a mixer, and a balanced detector, wherein the on-chip polarized light generating device is configured to provide polarized light to the beam splitter, wherein the beam splitter is configured to receive the light beam output from the on-chip polarized light generating device, and divides the light beam into a first portion of light transmitted to the light emitting and receiving device and a second portion of light transmitted to the mixer, wherein the light emitting and receiving device is configured to emit the first portion of light and to provide the received reflected first portion of light to the mixer, wherein the mixer is configured to mix the first portion of the light reflected back and the second portion of the light and transmit to the balanced detector, and wherein the balance detector is configured to detect a beat frequency between the reflected first portion of light and the second portion of light.
According to an embodiment of the present invention, there is provided a frequency modulated continuous wave lidar comprising an on-chip polarized light generating device, wherein the on-chip polarized light generating device comprises: the polarization rotating beam splitting device includes a polarization rotating beam splitting part PSR configured to separate a TE polarized light component and a TM polarized light component in input light to generate a first TE polarized light component, and convert the TM polarized light component into a second TE polarized light component, a first phase modulator pair and a second phase modulator pair configured to adjust optical paths of the first TE polarized light component and the second TE polarized light component, respectively, and a beam combiner configured to combine two adjusted TE polarized light components into one light.
According to an embodiment of the present invention, there is provided a frequency modulated continuous wave lidar comprising an on-chip polarized light generating device, wherein the on-chip polarized light generating device further comprises: the monitoring device comprises a monitoring beam splitter and a monitoring photoelectric detector MPD, wherein the monitoring beam splitter is configured to separate first monitoring light for monitoring from light synthesized by the beam combiner and provide the first monitoring light to the monitoring photoelectric detector MPD, and the monitoring photoelectric detector MPD is configured to monitor photocurrent of the first monitoring light.
According to an embodiment of the present invention, there is provided a frequency modulated continuous wave lidar including an on-chip polarized light generating device, wherein the first and second phase modulator pairs are adjusted according to a monitoring result of the monitoring photodetector MPD to adjust optical paths of respective TE polarized light components.
According to an embodiment of the invention, there is provided a frequency modulated continuous wave lidar comprising an on-chip polarized light generating device, wherein the balanced detector is further configured to remove common noise and DC signals from the first and second portions of light transmitted back.
According to an embodiment of the present invention, there is provided a frequency modulated continuous wave lidar comprising an on-chip polarized light generating device, wherein the light transmitting and receiving device comprises a light transmitter and a light receiver, or comprises a three-port circulator or a polarization beam splitting device.
According to an embodiment of the present invention there is provided a frequency modulated continuous wave lidar comprising an on-chip polarised light generating device, wherein the light source comprises a laser light source and a non-polarisation maintaining erbium doped fibre amplifier for providing an optical input to a silicon optical chip.
According to an embodiment of the present invention, there is provided a frequency modulated continuous wave lidar comprising an on-chip polarized light generating device, further comprising an optical phased array OPA configured to be coupled to the light emitting and receiving device and to control a direction of emission of light received from the light emitting and receiving device.
According to an embodiment of the present invention, there is provided a frequency modulated continuous wave lidar comprising an on-chip polarized light generating device, further comprising an 1/4 waveplate.
Technical effects
The cost of the laser radar system is reduced by replacing the polarization maintaining optical fiber between the laser and the optical chip with a non-polarization maintaining optical fiber; the laser radar based on the scheme does not need a polarization maintaining fiber amplifier EDFA any more, and only the non-polarization maintaining fiber amplifier EDFA is adopted, so that the cost of the laser radar system is further reduced; in addition, it makes full use of TM and TE polarized light, improving efficiency.
Drawings
The above and other aspects, features and advantages of particular embodiments of the present disclosure will become more apparent from the following description when taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic diagram showing the spectral time relationship of the transmitted and received light of a frequency modulated continuous wave lidar;
FIG. 2 is a schematic diagram showing the structure of a conventional frequency modulated continuous wave lidar;
FIG. 3A is a schematic diagram illustrating a frequency modulated continuous wave lidar in accordance with an embodiment of the invention;
FIG. 3B is a schematic diagram illustrating a structure of an on-chip polarized light generating device according to an embodiment of the invention;
FIG. 4 is a schematic diagram showing the structure of a frequency modulated continuous wave lidar including an on-chip polarized light generating apparatus according to an embodiment of the present invention;
FIG. 5 is a schematic diagram showing the structure of a frequency modulated continuous wave lidar including an on-chip polarized light generating apparatus according to another embodiment of the present invention;
FIG. 6 is a schematic diagram showing the structure of a frequency modulated continuous wave lidar including an on-chip polarized light generating apparatus according to another embodiment of the present invention; and
fig. 7 is a schematic diagram showing the structure of a frequency modulated continuous wave lidar including an on-chip polarized light generating apparatus according to another embodiment of the present invention.
Detailed Description
Before proceeding with the following detailed description, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The terms "include" and "comprise," as well as derivatives thereof, mean inclusion without limitation. The term "or" is inclusive, meaning and/or. The phrase "associated with … …" and derivatives thereof means including, included within … …, interconnected, contained within … …, connected or connected with … …, coupled or coupled with … …, in communication with … …, mated, interwoven, juxtaposed, proximate, bound or bound with … …, having an attribute, having a relationship or having a relationship with … …, and the like. The term "controller" refers to any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware, or a combination of hardware and software and/or firmware. The functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. The phrase "at least one of, when used with a list of items, means that a different combination of one or more of the listed items can be used and only one item in the list may be required. For example, "at least one of A, B, C" includes any one of the following combinations: A. b, C, A and B, A and C, B and C, A and B and C.
Definitions for other specific words and phrases are provided throughout this patent document. Those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.
In this patent document, the application combination of transform blocks and the division levels of sub-transform blocks are only for illustration, and the application combination of transform blocks and the division levels of sub-transform blocks may have different manners without departing from the scope of the present disclosure.
Figures 1 through 7, discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged system or device.
Fig. 2 is a schematic diagram showing the structure of a conventional frequency modulated continuous wave lidar.
Referring to fig. 2, light emitted from a laser light source 201 is amplified by a polarization maintaining fiber amplifier (polarization maintaining EDFA) 202 and then transmitted to a Fiber Array (FA) 203 through a polarization maintaining fiber. The fiber array 203 is connected to the silicon optical chip 200 of the on-chip frequency modulated continuous wave FMCW lidar and light from the laser source 201 is provided into the waveguide WG by a spot-size converter (SSC) 204. Thereafter, the light emitted from the laser light source is split into N beams by the optical splitter 205 and transmitted to the FMCW engine or OPA antenna array in the frequency modulated continuous wave FMCW lidar, where N is a positive integer greater than/equal to 1.
Since the devices on a silicon optical chip are sensitive to polarization, the input light is required to be polarized light. In general, the light emitted from the laser is polarized (usually TE polarized), so the optical fiber in the fiber amplifier EDFA and the optical fiber between the fiber amplifier EDFA and the light array FA must be polarization maintaining fiber to keep the polarization state of the light unchanged.
Fig. 3A is a schematic diagram showing the structure of a frequency modulated continuous wave lidar in accordance with an embodiment of the present invention.
Referring to fig. 3A, the light source includes a laser light source 301 and a non-polarization maintaining fiber amplifier EDFA 302 for providing an optical input to the silicon optical chip. Light emitted from a laser light source 301 is amplified by a non-polarization maintaining erbium-doped fiber amplifier (EDFA) 302 and then transmitted to a Fiber Array (FA) 303 through a non-polarization maintaining fiber. The fiber array 303 is connected to the silicon optical chip 300 of the on-chip frequency modulated continuous wave FMCW lidar and light from a laser light source 301 is provided into the waveguide WG by a spot-size converter (SSC) 304. Thereafter, the light transmitted through the waveguide WG generates polarized light via the on-chip polarized light generating device 306. The generated polarized light is split into N beams by the beam splitter 305 and transmitted to an FMCW engine or OPA antenna array in a frequency modulated continuous wave FMCW lidar.
Referring to fig. 3A, according to an embodiment of the present invention, an optical fiber amplifier (EDFA) 302 is a non-polarization-maintaining fiber amplifier, and the fiber is a non-polarization-maintaining fiber, so that the light input to the silicon optical chip is no longer polarized. In order for the silicon optical chip to operate normally, it is therefore necessary to convert unpolarized light input into the waveguide WG into polarized light by the on-chip polarized light generating device 306.
Fig. 3B is a schematic structural diagram illustrating an on-chip polarized light generating apparatus according to an embodiment of the present invention.
Referring to fig. 3B, the on-chip polarized light generating device 306 includes a polarization rotating beam splitting component (PSR) 307, a first phase modulator pair, a second phase modulator pair, a 3dB coupler 310, a beam combiner 313, a monitoring beam splitter 314, and a Monitoring Photodetector (MPD) 315 according to an embodiment of the present invention. The first phase modulator pair comprises a first phase modulator 308, a second phase modulator 309 and the second phase modulator pair comprises a third phase modulator 311, a fourth phase modulator 312.
Referring to fig. 3B, the polarization rotating beam splitting Part (PSR) 307 according to an embodiment of the present invention separates a TE polarized light component and a TM polarized light component in input light, while converting the TM polarized light component into the TE polarized light component.
The first phase modulator pair includes a first phase modulator 308 and a second phase modulator 309, where the first phase modulator 308 and the second phase modulator 309 are configured to adjust optical paths of the two TE polarized light components. The optical path-adjusted TE polarized light components are input to a 3dB coupler 310, and the 3dB coupler 310 is configured such that the two TE polarized components after the optical path adjustment by the first phase modulator 308 and the second phase modulator 309 constructively interfere. The light passing through the 3dB coupler 310 is input to the second phase modulator pair (third phase modulator 311 and fourth phase modulator 312) to adjust the optical lengths of the two TE polarized lights again.
The optical path lengths of the two beams of TE polarized light can be adjusted by using a first phase modulator pair (first phase modulator 308 and second phase modulator 309), a 3dB coupler 310, and a second phase modulator pair (third phase modulator 311 and fourth phase modulator 312). Two TE polarization components after the optical path lengths thereof are adjusted by the first phase modulator 308 and the second phase modulator 309 are constructively interfered by the 3dB coupler 310, and in addition, random variations in the polarization state of light in the non-polarization-maintaining fiber can be compensated for by the first phase modulator pair and the second phase modulator pair.
According to an embodiment of the invention, the first and second phase modulator pairs comprise III-V material, lithium niobate based phase modulators and thermal or electrical modulators, and may be integrated onto a silicon photonics chip by thermal (heater), electrical (carrier injection/deletion), or by way of heterogeneous integration.
Referring to fig. 3B, two TE polarized lights whose optical paths are adjusted by the second phase modulator pair (third phase modulator 311 and fourth phase modulator 312) are combined into one light by the beam combiner 313. Thereafter, according to an embodiment of the present invention, a portion of the combined light beam (preferably, less than a first threshold, e.g., less than 5% of the combined light) is split by the monitoring beam splitter 314 into a Monitoring Photo Detector (MPD) 315, which MPD 315 monitors the light beam. According to an embodiment of the present invention, the first phase modulator pair and the second phase modulator pair may be adjusted according to the monitoring result of the MPD, so that the output light is maintained in the TE polarization state. According to the embodiment of the present invention, when the monitoring photodetector MPD 315 monitors that the photocurrent of the light modulated by the first and second phase modulator pairs reaches a maximum, it indicates that the two TE polarized light components synthesized at the beam combiner 313 interfere constructively. According to the embodiment of the present invention, the first phase modulator pair and the second phase modulator pair may be adjusted according to the monitoring result of the monitoring photodetector MPD 315 to adjust the corresponding TE polarized light component, thereby implementing feedback control of the on-chip polarized light generating device 306.
Fig. 4 is a schematic diagram showing the structure of a frequency modulated continuous wave lidar including an on-chip polarized light generating apparatus according to an embodiment of the present invention.
Referring to fig. 4, a frequency modulated continuous wave lidar including an on-chip polarized light generating apparatus according to an embodiment of the present invention includes: a light source 401 and a silicon photo chip 400, wherein the light source 401 and the silicon photo chip 400 are connected by a non-polarization maintaining fiber. In some other examples, the light source 401 may also include a modulator that receives the modulated signal. The modulator may be configured to modulate the optical beam based on the modulation signal to produce the output light of fig. 1 with a frequency variation.
The silicon optical chip 400 according to an embodiment of the present invention includes: an on-chip polarized light generating device 402, a beam splitter 403, a light emitter 404, a light receiver 405, a mixer 406, and a balanced detector 407. Wherein the components of the silicon photonics chip 400 may be implemented in the form of an on-chip semiconductor module.
The on-chip polarized light generating device 402 is configured to receive light from the light source 401 and generate polarized light. The beam splitter 403 is configured to receive the light beam output from the on-chip polarized light generating device 402 and further split the light beam into a first portion of light and a second portion of light. A first portion of the light may be transmitted to optical transmitter 404 and a second portion of the light may be transmitted to mixer 406. The first portion of light and the second portion of light have the same frequency at any point in time.
According to an embodiment of the invention, light emitter 404 may be configured to emit a first portion of light at a predetermined angle. When the first portion of light emitted from the light emitter 404 is reflected from the surface of the object, the light receiver 405 may receive the reflected first portion of light. The first portion of the light reflected back may be further transmitted to the mixer 406. The second part of the light and the reflected first part of the light may be mixed in a mixer 406 and further transmitted to a balanced detector 407.
As shown in fig. 4, optical transmitter 404 and optical receiver 405 may be connected to two different ports of silicon optical chip 400.
The second part of the light and the first part of the light reflected back will be mixed in the mixer 406 and the mixed signal will be split into two branches and fed to the balanced detector 407.
The balanced detector 407 is configured to detect the beat frequency between the reflected first and second portions of light and to remove common noise and DC signals from both branches. The frequency of the signal detected by the balance detector 407 is the frequency difference between the first part of the reflected light and the second part of the reflected light, and is used to calculate the velocity and distance of the object surface relative to the frequency modulated continuous wave lidar. Based on the determination of the beat frequency signal frequency, the processing unit may further calculate the velocity and distance of the object surface relative to the frequency modulated continuous wave lidar according to equation 1 above.
Fig. 5 is a schematic diagram showing the structure of a frequency modulated continuous wave lidar including an on-chip polarized light generating apparatus according to another embodiment of the present invention.
Referring to fig. 5, the structure of the frequency modulated continuous wave lidar shown differs from that shown in fig. 4 in that the frequency modulated continuous wave lidar shown in fig. 5 includes a three-port circulator 504 in place of the optical transmitter 404 and the optical receiver 405.
The three-port circulator 504 can include three ports to receive and transmit light, respectively. Where a first portion of the light may be input to the three-port circulator 504 at port 1 (port 1) and output from port 2 (port 2). Light received from port 2 can be transmitted to port 3 (port 3) and further to mixer 505. According to the solution shown in fig. 5, the optical transmitter and the optical receiver can be integrated and share the same port.
Fig. 6 is a schematic diagram showing the structure of a frequency modulated continuous wave lidar including an on-chip polarized light generating apparatus according to another embodiment of the present invention.
Referring to fig. 6, the structure of the frequency modulated continuous wave lidar shown differs from that shown in fig. 4 in that the frequency modulated continuous wave lidar shown in fig. 6 includes a polarization beam splitting device 604 instead of the optical transmitter 404 and the optical receiver 405.
The polarization splitting device 604 may include three ports to receive and transmit light, respectively. Where a first portion of light can be input to the polarization splitting device 604 at port 1 (port 1), regardless of its polarization, and output from port 2 (port 2). Light received from port 2 can be divided based on polarization and transmitted to port 1 and port 3 (port 3), respectively. For example, the TE polarized light component received at port 2 may be transmitted to port 1, the TM polarized light component received at port 2 may be transmitted to port 3, and further transmitted to the mixer 605.
Fig. 7 is a schematic diagram showing the structure of a frequency modulated continuous wave lidar including an on-chip polarized light generating apparatus according to another embodiment of the present invention.
Referring to fig. 7, the structure of the frequency modulated continuous wave lidar shown differs from that shown in fig. 6 in that the frequency modulated continuous wave lidar shown in fig. 7 further includes Optical Phase Arrays (OPAs) 707 and 1/4 waveplates 708.
In accordance with an embodiment of the present invention, the OPA 707 is configured to control the direction of light by dynamically controlling the optical properties of the surface on a microscopic scale. For example, the OPA 707 can be configured to emit a first portion of the light beam emitted from the polarization splitting device 704 in a first direction and a second portion of the light beam in a second direction.
1/4 the wave plate 708 is configured to couple with the OPA 707 to prevent light from reflecting back into the cavity to affect the lasing state in the cavity.
The text and drawings of the present invention are provided as examples only to aid understanding of the present disclosure. They should not be construed as limiting the scope of the disclosure in any way.
Although the present disclosure has been described with exemplary embodiments, various changes and modifications may be suggested to one skilled in the art. The present disclosure is intended to embrace such alterations and modifications as fall within the scope of the appended claims.
None of the description in this specification should be read as implying that any particular element, step, or function is an essential element which must be included in the claim scope. The scope of patented subject matter is defined only by the claims.
Claims (10)
1. An on-chip polarized light generating device for frequency modulated continuous wave lidar comprising:
a polarization rotation beam splitting part PSR configured to separate a TE polarized light component and a TM polarized light component in input light to generate a first TE polarized light component and convert the TM polarized light component into a second TE polarized light component;
a first phase modulator pair and a second phase modulator pair configured to adjust optical paths of the first TE polarized light component and the second TE polarized light component, respectively; and
and the beam combiner is configured to combine the two TE polarized light components after adjustment into one light.
2. The on-chip polarized light generating apparatus for frequency modulated continuous wave lidar of claim 1, further comprising: a monitoring beam splitter and a monitoring photodetector MPD,
wherein the monitoring beam splitter is configured to separate first monitoring light for monitoring from the light combined by the beam combiner and provide the first monitoring light to a monitoring photodetector MPD,
wherein the monitoring photodetector MPD is configured to monitor a photocurrent of the first monitoring light.
3. The device for generating on-chip polarized light for frequency-modulated continuous wave lidar according to claim 2, wherein the first and second phase modulator pairs are adjusted according to a monitoring result of the monitoring photodetector MPD to adjust optical paths of the first and second TE polarized light components.
4. The on-chip polarized light generating apparatus for frequency modulated continuous wave lidar of claim 1, further comprising a 3dB coupler disposed between the first and second phase modulator pairs such that the first and second TE polarization components after passing through the first phase modulator pair to adjust the optical path constructively interfere.
5. The apparatus for on-chip polarized light generation for frequency modulated continuous wave lidar of claim 1, wherein the first phase modulator pair comprises a first phase modulator and a second phase modulator, and the second phase modulator pair comprises a third phase modulator and a fourth phase modulator, wherein
The first and second phase modulator pairs comprise phase modulators, thermal modulators or electrical modulators based on III-V materials or lithium niobate.
6. A frequency modulated continuous wave lidar including an on-chip polarized light generating apparatus according to any of claims 1-5, comprising:
a light source; and
a silicon optical chip connected to a light source through a non-polarization maintaining fiber, and comprising: an on-chip polarized light generating device, a beam splitter, a light emitting and receiving device, a mixer, and a balanced detector,
wherein the on-chip polarized light generating device is configured to provide polarized light to the beam splitter,
wherein the optical splitter is configured to receive the light beam output from the on-chip polarized light generating device and split the light beam into a first portion of light transmitted to the light emitting and receiving device and a second portion of light transmitted to the mixer,
wherein the light emitting and receiving device is configured to emit the first portion of light and to provide the received reflected first portion of light to the mixer,
wherein the mixer is configured to mix the first portion of the light reflected back and the second portion of the light and transmit to the balanced detector, an
Wherein the balance detector is configured to detect a beat frequency between the reflected first portion of light and the second portion of light.
7. The frequency modulated continuous wave lidar of claim 6, wherein the balance detector is further configured to remove common noise and DC signals from the reflected first and second portions of light.
8. Frequency modulated continuous wave lidar according to claim 6, wherein the light transmitting and receiving means comprises a light emitter and a light receiver or the light transmitting and receiving means comprises a three-port circulator or a polarization splitting device.
9. A frequency modulated continuous wave lidar according to claim 6, wherein the light source comprises a laser light source and a non-polarization maintaining fiber amplifier for providing an optical input to the silicon optical chip.
10. Frequency modulated continuous wave lidar according to claim 6, further comprising an optical phased array OPA configured to be coupled to the light emitting and receiving device and to control the emission direction of light received from the light emitting and receiving device.
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| CN202210738157.9A Pending CN114814788A (en) | 2022-06-28 | 2022-06-28 | On-chip polarized light generating device for frequency modulation continuous wave laser radar |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN115128734A (en) * | 2022-08-31 | 2022-09-30 | 上海羲禾科技有限公司 | Silicon optical chip and laser radar based on same |
| CN116087914A (en) * | 2023-04-10 | 2023-05-09 | 深圳市速腾聚创科技有限公司 | Laser radar and mobile device |
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| CN112764008A (en) * | 2020-12-28 | 2021-05-07 | 武汉光谷信息光电子创新中心有限公司 | Laser radar chip |
| US11092745B1 (en) * | 2020-02-14 | 2021-08-17 | Nokia Solutions & Networks Oy | Polarization controller |
| CN113452450A (en) * | 2021-06-25 | 2021-09-28 | 中国科学技术大学 | Light polarization modulation method, light polarization modulation module and light chip |
| WO2022112679A1 (en) * | 2020-11-24 | 2022-06-02 | Scintil Photonics | Photonic chip and photonic component integrating such a chip |
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| WO2022112679A1 (en) * | 2020-11-24 | 2022-06-02 | Scintil Photonics | Photonic chip and photonic component integrating such a chip |
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| CN116087914A (en) * | 2023-04-10 | 2023-05-09 | 深圳市速腾聚创科技有限公司 | Laser radar and mobile device |
| CN116087914B (en) * | 2023-04-10 | 2023-08-04 | 深圳市速腾聚创科技有限公司 | Laser radar and mobile device |
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