CN114325639A - Optical component and silicon optical chip for radar - Google Patents
Optical component and silicon optical chip for radar Download PDFInfo
- Publication number
- CN114325639A CN114325639A CN202011059984.2A CN202011059984A CN114325639A CN 114325639 A CN114325639 A CN 114325639A CN 202011059984 A CN202011059984 A CN 202011059984A CN 114325639 A CN114325639 A CN 114325639A
- Authority
- CN
- China
- Prior art keywords
- light
- phase retarder
- beam splitter
- polarized light
- echo
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 120
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 title claims description 69
- 229910052710 silicon Inorganic materials 0.000 title claims description 69
- 239000010703 silicon Substances 0.000 title claims description 69
- 230000010287 polarization Effects 0.000 claims abstract description 107
- 239000000523 sample Substances 0.000 claims description 31
- 238000001514 detection method Methods 0.000 claims description 17
- 230000010355 oscillation Effects 0.000 claims description 10
- 230000035559 beat frequency Effects 0.000 claims description 6
- 230000005540 biological transmission Effects 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 11
- 230000010354 integration Effects 0.000 description 9
- 238000005516 engineering process Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 3
- 238000002955 isolation Methods 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 230000008569 process Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 229910000577 Silicon-germanium Inorganic materials 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000001427 coherent effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 230000005693 optoelectronics Effects 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 238000007747 plating Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
Images
Landscapes
- Optical Radar Systems And Details Thereof (AREA)
Abstract
The present invention provides an optical assembly usable with radar, comprising: a polarization beam splitter configured such that a first port can receive first polarized light from a laser and output the first polarized light from a second port; and the phase retarder is configured to receive the first polarized light output by the second port from the polarization beam splitter, the first polarized light exits after passing through the phase retarder, the phase retarder is further configured to receive the echo of the radar, the echo is adjusted into second polarized light after passing through the phase retarder, is incident on the polarization beam splitter from the second port and is output from the third port, and the polarization direction of the first polarized light is perpendicular to the polarization direction of the second polarized light. By the embodiment of the invention, crosstalk and stray light can be effectively reduced, the ranging precision of the radar is improved, and a blind area is reduced.
Description
Technical Field
The present invention generally relates to the field of optoelectronic technologies, and in particular, to an optical component and a silicon optical chip for a laser radar.
Background
The silicon photon technology is a new generation technology based on silicon and silicon-based substrate materials (such as SiGe/Si, SOI and the like) and utilizing the existing CMOS process to develop and integrate optical devices, and combines the characteristics of ultra-large-scale and ultra-high-precision manufacturing of an integrated circuit technology and the advantages of ultra-high speed and ultra-low power consumption of the photon technology. The silicon photon architecture is mainly completed by a silicon-based laser, a silicon-based photoelectric integrated chip, an active optical component and optical fiber packaging. LiDAR (LiDAR) requires multiple laser emitters and receivers, or uses multi-channel signal control, and the high integration of silicon light and the electro-optic phase tuning capability are well suited for LiDAR applications.
The LiDAR adopting the pulse distance measurement has high pulse peak power and extremely small size of a silicon optical device, so that the power density in the device is high, laser power loss and heating temperature rise are caused, and nonlinearity is easily generated. Compared with a pulse ranging LiDAR, the peak power of a Frequency Modulated Continuous Wave (FMCW) radar is the continuous power of light emission, which is far lower than the pulse peak power, and the power density of a silicon optical device is not too high, so that the silicon optical technology is suitable for being applied to the FMCW radar.
The coaxial FMCW radar generally uses a circulator as a beam splitting device, the circulator has a magneto-optical effect, polarized light is subjected to Faraday deflection in the circulator, and light beam transmission is controlled through a 2-port and 3-port polarization separation device. As shown in the schematic diagram of the circulator in fig. 1, the probe light is input into the circulator from the 1 port and can only be output from the 2 port, and the echo light beam is input into the circulator from the 2 port and can only be output from the 3 port, thereby realizing the isolation of the transmitting and receiving light paths. But there is some crosstalk with the circulator, about-60 dB, i.e. a small fraction of probe light is emitted from 3, forming stray light. If the circulator is integrated on a silicon optical chip, the crosstalk reaches-30 dB. If a stray light signal is filtered by using a high-pass filter, a short-distance blind area of more than 2 meters can be caused; if the stray light is too strong, high-order harmonics of various orders can be generated, the range of a blind area is enlarged, and the short-distance detection of the laser radar is very adversely affected. Thus, the circulator becomes a significant obstacle to the chip formation of the FMCW radar optical device.
The statements in the background section are merely prior art as they are known to the inventors and do not, of course, represent prior art in the field.
Disclosure of Invention
Embodiments of the present invention solve the problems of crosstalk and stray light caused by using a circulator as a beam splitting device in the prior art by using a silicon optical chip comprising a polarization beam splitter or an optical coupler.
In view of at least one of the drawbacks of the prior art, the present invention proposes an optical assembly usable for radar, comprising:
a polarization beam splitter configured such that a first port can receive first polarized light from a laser and output the first polarized light from a second port;
a phase retarder configured to receive the first polarized light output from the second port from the polarization beam splitter, the first polarized light exiting after passing through the phase retarder, the phase retarder being further configured to receive an echo of the radar, the echo being adjusted to a second polarized light after passing through the phase retarder, and being incident on the polarization beam splitter from the second port and being output from a third port,
wherein the polarization direction of the first polarized light is perpendicular to the polarization direction of the second polarized light.
According to an aspect of the present invention, the polarization beam splitter further includes a mode converter, the second polarization light is incident to the polarization beam splitter, is converted into third polarization light by the mode converter, and is output from the third port, and the polarization direction of the third polarization light is the same as the polarization direction of the first polarization light.
According to an aspect of the present invention, the apparatus further includes a collimating lens disposed between the polarization beam splitter and the phase retarder, and a scanning unit disposed downstream of an optical path of the phase retarder, wherein the collimating lens is configured to receive the first polarized light from the polarization beam splitter, collimate the first polarized light to make the first polarized light enter the phase retarder, and output the first polarized light after the first polarized light is collimated by the phase retarder and scanned by the scanning unit, and the scanning unit is configured to receive the echo and return the echo to the phase retarder.
According to one aspect of the invention, the polarization beam splitter further comprises a collimating lens and a scanning unit which are sequentially arranged at the downstream of the phase retarder, the first polarized light respectively passes through the phase retarder, the collimating lens and the scanning unit and then is emitted, and the echo waves are scanned by the scanning unit and converged by the collimating lens and then enter the phase retarder.
According to an aspect of the invention, wherein the polarization beam splitter is integrated on a silicon optical chip, the phase retarder is arranged outside the silicon optical chip.
According to an aspect of the invention, wherein the polarization beam splitter and the phase retarder are integrated on one silicon optical chip.
According to one aspect of the invention, wherein the phase retarder is a quarter wave plate.
The invention also relates to a silicon optical chip for radar, comprising
A chip body;
the optical beam splitter receives a light beam emitted by a light source, divides the light beam into local oscillation light and detection light according to a certain proportion, and receives an echo reflected by a target object by the detection light, wherein the detection light is polarized light; and
a mixer that mixes the local oscillation light and the echo;
the chip body is provided with at least two ports, one port outputs the probe light and receives the echo, and the other port outputs a beat frequency signal obtained by mixing the local oscillator light and the echo by the frequency mixer.
According to an aspect of the present invention, wherein the optical beam splitter further includes a mode converter that converts a polarization state of the echo to be the same as the probe light.
According to one aspect of the invention, the silicon optical chip is combined with a phase retarder to perform phase modulation on the probe light and the echo.
According to one aspect of the invention, wherein the phase retarder is integrated in the silicon optical chip.
According to one aspect of the invention, wherein the beam splitter is a polarizing beam splitter.
According to one aspect of the invention, wherein the optical beam splitter is an optical coupler.
According to an aspect of the invention, an antireflection film is disposed on the light emitting surface of the silicon optical chip.
According to an aspect of the present invention, the light emitting surface of the silicon optical chip is an inclined surface, so that an included angle between the transmission direction of the detection light emitted from the silicon optical chip and the light emitting surface is not 90 degrees.
The embodiment of the invention integrates the polarization beam splitter or the optical coupler on the silicon optical chip instead of the circulator, does not need the circulator with high crosstalk to carry out light path isolation, greatly reduces stray light, further can reduce the filtering requirement, improve the signal-to-noise ratio, reduce the close-range blind area, and realize the light path control of coaxial transceiving in the chip, so that the radar can realize the chip of an optical device, improve the signal transmission speed, greatly improve the integration level of the device, be beneficial to reducing the volume of the laser radar and reduce the power consumption and the cost.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 shows a schematic of a circulator in the prior art;
FIG. 2 shows a schematic diagram of an optical assembly that may be used in an FMCW radar in accordance with one embodiment of the invention;
FIG. 3 shows a schematic diagram of an optical assembly that may be used in an FMCW radar in accordance with another embodiment of the invention;
FIG. 4 shows a schematic diagram of a silicon photonics chip in accordance with one embodiment of the present invention;
FIG. 5 shows a schematic diagram of a polarizing beam splitter according to one embodiment of the invention; and
FIG. 6 shows a schematic diagram of an optical coupler according to one embodiment of the present invention.
Detailed Description
In the following, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the description of the present invention, it should be noted that unless otherwise explicitly stated or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection, either mechanically, electrically, or in communication with each other; either directly or indirectly through intervening media, either internally or in any other relationship. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly above and obliquely above the second feature, or simply meaning that the first feature is at a lesser level than the second feature.
The following disclosure provides many different embodiments or examples for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Of course, they are merely examples and are not intended to limit the present invention. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples, such repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. In addition, the present invention provides examples of various specific processes and materials, but one of ordinary skill in the art may recognize applications of other processes and/or uses of other materials.
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
Fig. 2 shows a schematic diagram of an optical component that can be used in a lidar, in particular an FMCW radar, according to an embodiment of the invention. As shown, the optical assembly 100 includes: a polarizing beam splitter 110 and a phase retarder 120. The polarization beam splitter 110 has a plurality of ports, each of which can only receive polarized light with a predetermined polarization direction, and for incident polarized light with a predetermined polarization direction, the polarized light exits from another predetermined port. For example, the polarization beam splitter 110 is configured such that the first port 110-1 can receive light of a first polarization, e.g., TE mode, and output the light of the first polarization from the second port 110-2. The phase retarder 120 is configured to receive the first polarized light output from the second port 110-2 from the polarization beam splitter 110, the first polarized light exits after passing through the phase retarder 120, the phase retarder 120 is further configured to receive the echo of the FMCW radar, the echo is adjusted to be the second polarized light after passing through the phase retarder 120, wherein the polarization direction of the first polarized light is perpendicular to the polarization direction of the second polarized light. The second polarized light is incident from the second port 110-2 of the polarization beam splitter 110, modulated into third polarized light, and output from the third port 110-3. Optionally, a coupler (not shown in the figure) is further disposed in an optical path downstream of a light source (e.g., a laser) of the first polarized light, and the coupler splits laser light emitted by the light source into local oscillation light and first polarized light for detection according to a certain preset ratio, where the first polarized light for detection is incident from the first port 110-1 of the polarization beam splitter 110. The optical component 100 further includes a mixer 230, where the mixer 230 receives the local oscillator light and the third polarized light emitted from the third port 110-3 of the polarization beam splitter 110, and the mixer 230 mixes the local oscillator light and the third polarized light (echo) to obtain a beat signal and then outputs the beat signal, and according to the beat signal, information such as a distance and a speed of the target object can be obtained through calculation.
According to an embodiment of the present invention, as shown in fig. 2, the polarization beam splitter 110 further includes a mode converter 111, the second polarized light adjusted by the phase retarder 120 is incident to a second port 110-2 of the polarization beam splitter 110, and is converted into a third polarized light by the mode converter 111 and output from a third port 110-3, and a polarization direction of the third polarized light is the same as a polarization direction of the first polarized light. Preferably, the polarization state of the first polarized light incident from the first port 110-1 is unchanged after passing through the mode converter 111.
According to an embodiment of the present invention, as shown in fig. 2, the optical assembly 100 further includes a collimating lens 130 and a scanning unit 140, the collimating lens 130 is disposed between the polarization beam splitter 110 and the phase retarder 120, the scanning unit 140 is disposed in the optical path downstream of the phase retarder 120, the collimating lens 130 is configured to receive the first polarized light from the polarization beam splitter 110, collimate the first polarized light to be incident on the phase retarder 120 as parallel light, the collimated first polarized light is modulated by the phase retarder 120 and emitted after being scanned by the scanning unit 140 to reach a certain field range, the scanning unit 140 is configured to receive the echo and scan the echo to the phase retarder 120, the echo is collected by the collimating lens 130 after passing through the phase retarder 120, the collected echo, that is, the second polarized light is incident from the second port 110-2 of the polarization beam splitter 110, converted into the third polarized light by the mode converter 111, and emitted from the third port 110-3 of the polarization beam splitter 110.
According to one embodiment of the present invention, the phase retarder 120 is a quarter-wave plate. The function of the phase retarder is explained here: if the phase retarder is not provided, it is assumed that the first polarized light (probe light) received from the light source (e.g., laser) is a Transverse electric wave (TE mode), enters from the first port 110-1 of the polarization beam splitter 110, exits through the second port 110-2 of the polarization beam splitter 110 while maintaining the TE mode, is collimated by the collimator lens 130, exits as parallel light, and irradiates the scanning unit 140, and is reflected by the scanning unit 140 to reach a certain FOV. The light in TE mode is used as the probe light (first polarized light), although the polarization of the echo light beam reflected by the target is degraded, the echo light beam is still in TE mode in a large probability, and the polarization beam splitter 110 cannot deflect the echo light beam incident from the 110-2 end to an output port other than the 110-1 end, so that the echo light beam and the probe light emitting optical path are overlapped and polarization beam splitting cannot be effectively realized. Because the phase retarder 120 (e.g., a quarter wave plate) is disposed, the probe light and the echo light respectively pass through the phase retarder 120, after twice deflection, the TE mode light becomes a Transverse Magnetic (TM) mode light, at this time, the polarization state of the echo light is different from that of the probe light, and after passing through the polarization beam splitter, the echo light is deflected to the third port by the polarization beam splitting action and output to the mixer 230. By using the scheme, the integration of the coaxial transceiving scheme is realized, and the crosstalk and the stray light can be effectively reduced.
According to another embodiment of the present invention, as shown in fig. 3, a schematic diagram of an optical assembly applicable to an FMCW radar is shown, wherein a collimating lens 130 and a scanning unit 140 of the optical assembly 100 are respectively disposed in sequence downstream of an optical path of the phase retarder 120, a first port 110-1 of the polarization beam splitter 110 receives a first polarized light from the light source and outputs the first polarized light from a second port 110-2, the output first polarized light is respectively collimated by the phase retarder 120 and the collimating lens 130 and scanned by the scanning unit 140 and then emitted, the scanning unit 140 receives and reflects an echo of the FMCW radar, the reflected echo is condensed by the collimating lens 130 and then incident on the phase retarder 120 to become a second polarized light, the second port 110-2 of the polarization beam splitter 110 receives the incident second polarized light, converted into light of a third polarization by the mode converter 111 therein, and emitted from the third port 110-3.
According to an embodiment of the present invention, as shown in fig. 2, wherein the polarization beam splitter 110 is integrated on a silicon optical chip 200, the phase retarder 120 is disposed outside the silicon optical chip 200, and specifically, the collimating lens 130, the phase retarder 120 and the scanning unit 140 are disposed in sequence downstream of the polarization beam splitter 110 in the optical path and are all located outside the silicon optical chip 200. Preferably, the mixer 230 is also disposed on the silicon optical chip 200.
According to an embodiment of the present invention, as shown in fig. 3, wherein the polarization beam splitter 110 and the phase retarder 120 are integrated on a silicon optical chip 200, the collimating lens 130 and the scanning unit 140 are sequentially disposed in the optical path downstream of the phase retarder 120, and are both located outside the silicon optical chip 200. Preferably, the mixer 230 is also disposed on the silicon optical chip 200.
The invention also relates to a silicon optical chip which can be used for FMCW radar. Fig. 4 shows a schematic diagram of a silicon optical chip according to an embodiment of the present invention, where the silicon optical chip 200 includes a chip body 210, an optical splitter 220 and a mixer 230, where the optical splitter 220 and the mixer 230 are integrated on the chip body 210, the optical splitter 220 receives probe light transmitted from a light source (not shown in the figure), the light emitted from the light source is further separated into a part as local oscillation light, and the local oscillation light is directly output to the mixer 230. Preferably, the optical coupler 150 may be connected to the light source to split the light emitted from the light source into two parts, i.e., probe light and local oscillator light. The optical splitter 220 emits the probe light and receives an echo reflected by a target object, and the mixer 230 mixes the local oscillation light and the echo to obtain a beat frequency signal and outputs the beat frequency signal. The local oscillator light and the probe light are both polarized light, and the polarization directions of the local oscillator light and the echo output by the optical splitter 220 are the same.
According to an embodiment of the present invention, the beam splitter 220 is a polarization beam splitter 110. Referring to fig. 2, the polarization beam splitter 110 receives probe light, i.e., first polarized light, the probe light is emitted by the polarization beam splitter 110, an echo reflected by a target, i.e., second polarized light, is received by the polarization beam splitter 110, and third polarized light is output, and the third polarized light and local oscillation light from a light source are mixed in the mixer 230 to output a beat signal.
According to an embodiment of the present invention, a phase retarder is further disposed inside the silicon optical chip 210. Referring to fig. 3, if the phase retarder is not provided, it is assumed that the first polarized light (probe light) received from the light source (e.g., laser) is in TE mode, enters from the first port 110-1 of the polarization beam splitter 110, exits through the second port 110-2 of the polarization beam splitter 110 while maintaining the TE mode, is collimated by the collimating lens 130, exits as parallel light, and irradiates the scanning unit 140, and is reflected by the scanning unit 140 to reach a certain FOV. The light in TE mode is used as the probe light (first polarized light), although the polarization of the echo light beam reflected by the target is degraded, the echo light beam is still in TE mode, and the polarization beam splitter 110 cannot deflect the echo light beam whose main component is TE mode incident at the 110-2 end to the output port other than 110-1, so that the echo light beam and the probe light optical path are overlapped and polarization beam splitting cannot be effectively realized. The phase retarder 120 is disposed inside the silicon optical chip 210, the original TE mode detection light output by the polarization beam splitter 110 is deflected by the phase retarder 120, the polarization state changes, and then the echo light beam corresponding to the TE mode is deflected by the phase retarder 120 again to become TM mode light, at this time, the echo light beam input to the polarization beam splitter 110 is different from the polarization state of the output detection light, and after passing through the polarization beam splitter, the echo light beam is deflected to the third port by the polarization beam splitting effect to be output to the mixer 230. The phase retarder is optionally a quarter-wave plate. By using the scheme, the integration of the coaxial transceiving scheme is realized, and the crosstalk and the stray light can be effectively reduced.
FIG. 5 shows a schematic diagram of a polarizing beam splitter according to one embodiment of the invention. Referring to fig. 5, the polarization beam splitter 110 has three ports, a first port 110-1, a second port 110-2, and a third port 110-3. Specifically, as shown in fig. 5, the first port 110-1 receives probe light, which is first polarized light, and in this embodiment, the probe light is in TE mode. The probe light (first polarized light) in the TE mode directly exits through the polarization beam splitter 110, for example, exits through the phase retarder 120 (as shown in fig. 2 or fig. 3) downstream of the polarization beam splitter 110, and in this case, the returned echo light beam is the TM mode, i.e., the second polarized light. The echo beam (second polarized light) of the TM mode is input to the polarization beam splitter 110 from the second port 110-2. According to an embodiment of the present invention, as shown in fig. 5, the mode converter 111 of the polarization beam splitter 110 includes a first mode converter 111-1 and a second mode converter 111-2. Wherein the first mode converter 111-1 converts the received echo of the TM mode (second polarized light) into TE1Mold, TE1The light of the mode is coupled to the second mode converter 111-2 so as to be separated from the optical path of the probe light (first polarized light). The second mode converter 111-2 converts TE1The light in the mode is converted into the TE mode, so that the echo light in the TE mode having the same polarization state as the probe light (the first polarized light), i.e., the third polarized light, is obtained and output from the third port 110-3.
The polarization beam splitter 110 of the present embodiment is integrated in the silicon optical chip 210, and the polarization beam splitter 110 and the mode converters 111-1 and 111-2 are both formed by silicon waveguides.
Through the polarization beam splitter including the mode converter in this embodiment, the polarization states of the first polarized light as the probe light and the obtained echo are different, that is, the optical paths of the echo and the probe light can be separated, so that coaxial transceiving of the laser radar is realized. And the polarization state of the echo is converted to be the same as that of the first polarized light, and then the polarization state of the echo light output to the detector is the same as that of the local oscillator light, so that the detector is ensured to obtain beat frequency signals, and distance and/or speed data are obtained by processing according to the beat frequency signals. The polarization beam splitter of this embodiment comprises the silicon waveguide in the silicon optical chip, can realize beam split and mode conversion through the parameter design of silicon waveguide, gives full play to the advantage of the high integrated level of silicon optical chip, reduces the crosstalk that traditional light splitting component such as circulator caused to effectively reduce stray light, reduce radar blind area scope.
According to an embodiment of the present invention, the optical splitter 220 is an optical coupler 221. Fig. 6 is a schematic diagram of an optical coupler according to an embodiment of the present invention, and as shown in the figure, the optical coupler 221 has two inputs and two outputs respectively, and a wave division ratio can be set in advance for detecting a target object. Optionally, the splitting ratio is 99:1, that is, after all the light emitted by the light source is input from a and passes through the optical coupler 221, 99% of the light from the light source is output from C for detection, that is, the light is detected, and 1% of the light from the light source is output from D as local oscillation light. The echo of the probe light reflected by the target object is incident to the optical coupler 221 from C, wherein 99% of the echo is output from B and can be used for subsequent coherent detection, and 1% of the echo is output from a. The energy of the echo beam is relatively low, and only 1% of the echo energy is output from A, and the influence of the small part of light on the light source is negligible. Referring to fig. 4, the optical coupler 221 may be fully integrated on the silicon optical chip 200, which increases the integration of the chip and reduces the cost, and may be used for short-range FMCW radar for ranging with the same transmission power.
In this embodiment, the probe light and the local oscillator light may also adopt polarized light with the same polarization state, and the echo light beam and the local oscillator light also have the same polarization state, and after being coupled and emitted by the optical coupler, the echo light beam and the local oscillator light still can keep the original polarization state, and can be mixed with the local oscillator light to obtain a beat signal.
According to an embodiment of the invention, in order to reduce or avoid the influence of stray light, an antireflection film is disposed on the light emitting surface of the silicon optical chip. The light-emitting surface of the silicon optical chip may generate partial reflection, and the reflected light returning along the original path forms stray light. The reflectivity of the antireflection film is about 1 per mill, and the reflection caused by stray light can be reduced to an acceptable degree by plating the antireflection film on the light-emitting surface of the silicon optical chip, so that the influence of the stray light is effectively reduced.
According to an embodiment of the present invention, in order to reduce or avoid the influence caused by stray light, the light emitting surface of the silicon optical chip is set to be an inclined surface, so that an included angle between a light beam emitted by the silicon optical chip and the light emitting surface is not 90 degrees, and thus even if a part of light is reflected on the light emitting surface, the part of light cannot return to the emitting end along the original path, so that the detection light path is not influenced or slightly influenced.
The embodiment of the invention integrates the optical beam splitter such as a polarization beam splitter or an optical coupler on the silicon optical chip, realizes the integration of coaxial receiving and transmitting of the detection light in the silicon optical chip, improves the chip integration level, effectively reduces crosstalk and stray light, reduces light loss and cost, solves the problem of large crosstalk of a circulator integrated on the silicon optical chip in the prior art, enables the FMCW radar to realize the chip of an optical device, improves the stability of an optical path, greatly improves the integration level of the device, is beneficial to reducing the volume of the laser radar, and reduces the power consumption and the cost.
Those skilled in the art can understand that the technical scheme of the present invention is not only applicable to FMCW radars, but also applicable to other radars based on optical waveguides, such as radars or scanners using Absolute Distance Meters (ADMs), and can implement isolation of transmit and receive optical paths and achieve the technical effects of low crosstalk, low cost and high integration level.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (15)
1. An optical assembly usable with radar, comprising:
a polarization beam splitter having at least three ports, configured such that a first port can receive light of a first polarization from the laser and output the light of the first polarization from a second port thereof;
a phase retarder configured to receive the first polarized light output from the second port from the polarization beam splitter, the first polarized light exiting after passing through the phase retarder, the phase retarder being further configured to receive an echo of the radar, the echo being adjusted to a second polarized light after passing through the phase retarder, and being incident on the polarization beam splitter from the second port and being output from a third port,
wherein the polarization direction of the first polarized light is perpendicular to the polarization direction of the second polarized light.
2. The optical assembly of claim 1, wherein the polarization beam splitter further comprises a mode converter, the second polarized light is incident to the polarization beam splitter, converted into a third polarized light by the mode converter, and output from the third port, and the polarization direction of the third polarized light is the same as the polarization direction of the first polarized light.
3. The optical assembly of claim 1, further comprising a collimating lens disposed between the polarizing beam splitter and the phase retarder, the collimating lens configured to receive the first polarized light from the polarizing beam splitter, collimate the first polarized light to be incident on the phase retarder, the collimated first polarized light exiting through the phase retarder after being scanned by the scanning unit, and a scanning unit disposed in an optical path downstream of the phase retarder, the scanning unit configured to receive the echo and return to the phase retarder.
4. The optical assembly of claim 1, further comprising a collimating lens and a scanning unit sequentially disposed downstream of the phase retarder, wherein the first polarized light respectively exits after passing through the phase retarder, the collimating lens, and the scanning unit, and the echo is scanned by the scanning unit and condensed by the collimating lens to enter the phase retarder.
5. The optical assembly of any one of claims 1-3, wherein the polarizing beam splitter is integrated on a silicon optical chip, the phase retarder being disposed external to the silicon optical chip.
6. The optical assembly of any one of claims 1, 2, 4, wherein the polarizing beam splitter and phase retarder are integrated on one silicon optical chip.
7. The optical assembly of any one of claims 1-4, wherein the phase retarder is a quarter-wave plate.
8. A silicon optical chip for radar comprises
A chip body;
the optical beam splitter receives a light beam emitted by a light source, divides the light beam into local oscillation light and detection light according to a certain proportion, and receives an echo reflected by a target object by the detection light, wherein the detection light is polarized light; and
a mixer that mixes the local oscillation light and the echo;
the chip body is provided with at least two ports, one port outputs the probe light and receives the echo, and the other port outputs a beat frequency signal obtained by mixing the local oscillator light and the echo by the frequency mixer.
9. The silicon optical chip of claim 8, wherein the optical splitter further comprises a mode converter that converts the polarization state of the echo to be the same as the probe light.
10. The silicon optical chip of claim 8, wherein the silicon optical chip incorporates a phase retarder to phase modulate the probe light and the echo.
11. The silicon photonics chip of claim 10, wherein the phase retarder is integrated in the silicon photonics chip.
12. A silicon photonics chip as claimed in claim 8 or 9 wherein the beam splitter is a polarizing beam splitter.
13. A silicon photonics chip as claimed in claim 8 or 9 wherein the optical beam splitter is an optical coupler.
14. The silicon optical chip as claimed in claim 8 or 9, wherein an anti-reflection film is disposed on the light-emitting surface of the silicon optical chip.
15. The silicon optical chip as claimed in claim 8 or 9, wherein the light emitting surface of the silicon optical chip is disposed as an inclined surface, so that an included angle between the transmission direction of the detection light emitted from the silicon optical chip and the light emitting surface is not 90 degrees.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011059984.2A CN114325639A (en) | 2020-09-30 | 2020-09-30 | Optical component and silicon optical chip for radar |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011059984.2A CN114325639A (en) | 2020-09-30 | 2020-09-30 | Optical component and silicon optical chip for radar |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN114325639A true CN114325639A (en) | 2022-04-12 |
Family
ID=81011638
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011059984.2A Pending CN114325639A (en) | 2020-09-30 | 2020-09-30 | Optical component and silicon optical chip for radar |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114325639A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115128581A (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 |
| 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 |
| CN115421151A (en) * | 2022-11-02 | 2022-12-02 | 北京摩尔芯光半导体技术有限公司 | Laser radar |
| CN115639543A (en) * | 2022-12-14 | 2023-01-24 | 深圳市速腾聚创科技有限公司 | Frequency modulated continuous wave laser radar and autopilot equipment |
| CN115685147A (en) * | 2022-12-14 | 2023-02-03 | 深圳市速腾聚创科技有限公司 | Frequency modulated continuous wave laser radar and autopilot equipment |
| CN116087913A (en) * | 2023-04-10 | 2023-05-09 | 深圳市速腾聚创科技有限公司 | Optical chip, laser radar, automatic driving system and movable equipment |
| 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 |
| CN116719044A (en) * | 2023-08-10 | 2023-09-08 | 赛丽科技(苏州)有限公司 | Frequency modulation continuous wave laser radar |
| CN116908811A (en) * | 2023-09-12 | 2023-10-20 | 深圳市速腾聚创科技有限公司 | Optical chip, laser radar and mobile device |
| CN117075084A (en) * | 2023-09-25 | 2023-11-17 | 深圳市速腾聚创科技有限公司 | Optical chip, laser radar and mobile device |
-
2020
- 2020-09-30 CN CN202011059984.2A patent/CN114325639A/en active Pending
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115128581A (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 |
| 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 |
| CN115128581B (en) * | 2022-08-31 | 2022-12-20 | 上海羲禾科技有限公司 | Silicon optical chip and laser radar based on same |
| CN115128734B (en) * | 2022-08-31 | 2023-09-15 | 上海羲禾科技有限公司 | Silicon optical chip and laser radar based on same |
| CN115421151A (en) * | 2022-11-02 | 2022-12-02 | 北京摩尔芯光半导体技术有限公司 | Laser radar |
| CN115639543A (en) * | 2022-12-14 | 2023-01-24 | 深圳市速腾聚创科技有限公司 | Frequency modulated continuous wave laser radar and autopilot equipment |
| CN115685147A (en) * | 2022-12-14 | 2023-02-03 | 深圳市速腾聚创科技有限公司 | Frequency modulated continuous wave laser radar and autopilot equipment |
| US12025739B1 (en) | 2022-12-14 | 2024-07-02 | Suteng Innovation Technology Co., Ltd. | Frequency modulated continuous wave LiDAR and autonomous driving 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 |
| 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 |
| CN116087913A (en) * | 2023-04-10 | 2023-05-09 | 深圳市速腾聚创科技有限公司 | Optical chip, laser radar, automatic driving system and movable equipment |
| CN116719044A (en) * | 2023-08-10 | 2023-09-08 | 赛丽科技(苏州)有限公司 | Frequency modulation continuous wave laser radar |
| CN116719044B (en) * | 2023-08-10 | 2023-11-21 | 赛丽科技(苏州)有限公司 | Frequency modulation continuous wave laser radar |
| CN116908811A (en) * | 2023-09-12 | 2023-10-20 | 深圳市速腾聚创科技有限公司 | Optical chip, laser radar and mobile device |
| CN116908811B (en) * | 2023-09-12 | 2023-12-12 | 深圳市速腾聚创科技有限公司 | Optical chip, laser radar and mobile device |
| CN117075084A (en) * | 2023-09-25 | 2023-11-17 | 深圳市速腾聚创科技有限公司 | Optical chip, laser radar and mobile device |
| CN117075084B (en) * | 2023-09-25 | 2024-01-16 | 深圳市速腾聚创科技有限公司 | Optical chip, laser radar and mobile device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114325639A (en) | Optical component and silicon optical chip for radar | |
| CN110244281B (en) | Laser radar system | |
| CN109991582B (en) | Silicon-based hybrid integrated laser radar chip system | |
| CN111007483B (en) | Laser radar based on silicon optical chip | |
| CN115639543B (en) | Frequency modulation continuous wave laser radar and automatic driving equipment | |
| CN112764050B (en) | Laser radar measurement method and laser radar system | |
| KR102618374B1 (en) | LIDAR device with optical amplifier in return path | |
| CN114460601B (en) | Laser radar system | |
| CN114779277A (en) | Frequency modulated continuous wave lidar | |
| WO2023019498A1 (en) | Optical-path switching channel and switching method for measuring three-dimensional air volume on basis of dwdm optical switch module, and laser radar | |
| CN115542345A (en) | FMCW laser radar, automatic driving system and movable equipment | |
| CN115128580B (en) | Laser radar device | |
| CN114895318A (en) | Laser radar system | |
| JP2024517315A (en) | Quasi-monostatic LIDAR with 2D silicon photonic MEMS switch array | |
| CN112130130B (en) | Silicon optical chip and laser radar system | |
| WO2024045550A1 (en) | Laser radar transmitting module, transceiver device and laser radar | |
| CN116626696A (en) | Frequency modulation continuous wave laser range unit | |
| CN114895281B (en) | Method and device for generating target information by intrinsic signals and target return signals | |
| EP4286893A1 (en) | Detection apparatus, laser radar, chip and terminal device | |
| CN116908815B (en) | Laser radar and mobile device | |
| CN116736265B (en) | Optical chip, FMCW laser radar and movable device | |
| CN115656983B (en) | Continuous laser for coherent laser radar | |
| WO2024108407A1 (en) | Optical signal processing device, optical chip, detection device, and terminal | |
| CN117706517A (en) | Laser radar and mobile device | |
| CN116973926A (en) | Laser radar |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |