LiDAR devices with improved signal-to-noise ratio

Abstract

A light detection and ranging (LiDAR) device is provided, comprising: a light source configured to generate light; a light emitter configured to emit the light generated by the light source to an exterior of the LiDAR device; a light receiver configured to receive light from an exterior of the LiDAR device; a resonant photodetector configured to selectively amplify and detect light received by the light receiver having a wavelength identical to that of the light generated by the light source; and a processor configured to control the light source and the resonant photodetector, wherein the resonant photodetector comprises: a resonator; a phase modulator disposed on the resonator and configured to control the phase of light traveling along the resonator based on the control of the processor; and a light detector configured to detect the intensity of light traveling along the resonator.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2020-0082264, filed on July 3, 2020, with the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The exemplary embodiments of this disclosure relate to optical detection and ranging (LiDAR) devices, and more specifically, to LiDAR devices with improved signal-to-noise ratios. Background Technology

[0004] Recently, advanced driver assistance systems (ADAS) with various functions have been commercialized. For example, there is a growing trend in the number of vehicles equipped with features such as adaptive cruise control (ACC) and automatic emergency braking (AEB). ACC identifies the position and speed of other vehicles; if there is a risk of collision, it reduces the vehicle's speed; otherwise, it maintains the vehicle within a set speed range. AEB identifies vehicles ahead and automatically applies the brakes to prevent a collision if there is a risk but the driver has not responded or has responded inappropriately. Furthermore, autonomous vehicles are expected to be commercialized in the near future.

[0005] Therefore, vehicle radar, which provides information about what lies ahead of the vehicle, is becoming increasingly important. For example, LiDAR (Light Detection and Ranging) sensors are widely used in vehicle radar. LiDAR sensors measure the distance, velocity, azimuth, and position of an object based on the time it takes for scattered or reflected laser light to return, changes in laser intensity, changes in laser frequency, and changes in laser polarization state. Summary of the Invention

[0006] Additional aspects will be set forth in part in the description which follows, and will also be apparent in part from the description, or may be learned by practice of exemplary embodiments of this disclosure.

[0007] According to one aspect of an example embodiment, a light detection and ranging (LiDAR) device is provided, comprising: a light source configured to generate light; a light emitter configured to emit the light generated by the light source to an exterior of the LiDAR device; a light receiver configured to receive light from an exterior of the LiDAR device; a resonant photodetector configured to selectively amplify and detect light received by the light receiver having a wavelength identical to that of the light generated by the light source; and a processor configured to control the light source and the resonant photodetector, wherein the resonant photodetector includes: a resonator; a phase modulator disposed on the resonator and configured to control the phase of light traveling along the resonator based on the processor's control; and a light detector configured to detect the intensity of light traveling along the resonator.

[0008] The processor can also be configured to: provide light to a resonator before providing light generated by the light source to the light emitter; adjust the phase of the light traveling along the resonator by controlling a phase tuner so that the resonant wavelength of the resonator matches the wavelength of the light generated by the light source; and provide light generated by the light source to the light emitter after the resonant wavelength of the resonator is determined.

[0009] The processor can also be configured to: while adjusting the phase of the light traveling along the resonator by controlling the phase tuner, determine that the resonant wavelength of the resonator matches the wavelength of the light generated by the light source when the intensity of the light detected by the resonant photodetector reaches its maximum value.

[0010] The LiDAR device may further include: a temperature sensor configured to measure the temperature of a light source, wherein the processor is configured to: determine the wavelength of light generated by the light source based on the temperature measured by the temperature sensor, and adjust the phase of the light traveling along a resonator by controlling a phase tuner based on a change in the wavelength of the light generated by the light source exceeding a predetermined range, so that the resonant wavelength of the resonator matches the wavelength of the light generated by the light source.

[0011] The LiDAR device may also include: a first waveguide disposed between a light source and a light emitter; a second waveguide disposed between a light source and a resonator; a third waveguide disposed between a light receiver and a resonator; and an optical switch configured to provide light generated by the light source to the first waveguide or to the second waveguide based on processor control.

[0012] The LiDAR device may also include an additional photodetector connected to the end of a third waveguide, the additional photodetector being configured to measure the intensity of external noise.

[0013] The LiDAR device may also include: an optical coupler on a first waveguide, wherein an end of a second waveguide extends to the optical coupler, and a portion of the light supplied to the optical emitter through the first waveguide is supplied to the resonator through the optical coupler and the second waveguide.

[0014] The light source may include: a continuous wave light source configured to generate continuous wave light, wherein the processor is further configured to: control the light source to generate frequency-modulated light, and extract at least one of distance information and velocity information of an external object using a frequency-modulated continuous wave (FMCW) method.

[0015] The resonator may include: a first resonator and a second resonator, having different optical path lengths and being optically connected to each other, wherein the phase modulator includes: a first phase modulator disposed on the first resonator and configured to control the phase of light traveling along the first resonator based on processor control, and a second phase modulator disposed on the second resonator and configured to control the phase of light traveling along the second resonator based on processor control, and wherein the photodetector includes: a first photodetector configured to detect the intensity of light traveling along the first resonator, and a second photodetector configured to detect the intensity of light traveling along the second resonator.

[0016] The processor can also be configured to: provide light generated by the light source to a first resonator before providing light generated by the light source to the light emitter; adjust the phase of the light traveling along the first resonator by controlling a first phase modulator so that the resonant wavelength of the first resonator matches the wavelength of the light generated by the light source; adjust the phase of the light traveling along the second resonator by controlling a second phase modulator so that the resonant wavelength of the second resonator matches the wavelength of the light generated by the light source; and provide light generated by the light source to the light emitter after determining the resonant wavelengths of the first and second resonators.

[0017] The LiDAR device may also include: a first waveguide disposed between a light source and a light emitter; a second waveguide disposed between a light source and a first resonator; a third waveguide disposed between a light receiver and a second resonator; and an optical switch configured to provide light generated by the light source to the first waveguide or to the second waveguide based on processor control.

[0018] The LiDAR device may further include: a first waveguide disposed between the light source and the light emitter; an optical coupler disposed on the first waveguide; a second waveguide disposed between the optical coupler and the resonator; and a third waveguide disposed between the light receiver and the resonator, wherein a portion of the light supplied to the light emitter via the first waveguide is supplied to the resonator via the optical coupler and the second waveguide.

[0019] Resonators can include closed-curve waveguide resonators.

[0020] The resonator may include a first and a second ring mirror disposed on the waveguide, and a phase modulator and a photodetector may be disposed on the waveguide and between the first and second ring mirrors.

[0021] The LiDAR device may also include: a first waveguide disposed between a light source and a light emitter; a second waveguide disposed between a light source and a first circular mirror; a third waveguide disposed between a light receiver and a second circular mirror; and an optical switch configured to provide light generated by the light source to the first waveguide or to the second waveguide based on processor control.

[0022] The optical transmitter and optical receiver may each include an optical phased array (OPA) device.

[0023] The optical transmitter may further include: a substrate; a plurality of waveguides disposed on the substrate; a plurality of beam splitters, each including: an input terminal connected to one of the plurality of waveguides, and an output terminal connected to at least two of the plurality of waveguides; a plurality of phase control elements configured to independently control the phase of the multiple beams of light split by the plurality of beam splitters; and a plurality of grating pattern groups, each connected to the plurality of phase control elements and configured to emit the multiple beams of light whose phases are controlled.

[0024] The light source, light emitter, light receiver, and resonant photodetector can be mounted on the substrate.

[0025] The processor can also be configured to: control the azimuth direction of the light emitted by the light emitter by adjusting the phase of the separated light by controlling multiple phase control elements; and control the elevation direction of the light emitted by the light emitter by controlling the wavelength of the light generated by the light source.

[0026] The processor can also be configured to, based on the change in the elevation angle of the light emitted by the light emitter, control the phase modulator to match the resonant wavelength of the resonator with the wavelength of the light generated by the light source.

[0027] The processor can also be configured to: control a light source to generate light of a first wavelength; provide the light of the first wavelength generated by the light source to a resonator; adjust the phase of the light traveling along the resonator by controlling a phase modulator so that the resonant wavelength of the resonator matches the first wavelength; while providing the light of the first wavelength generated by the light source to the light emitter, control the azimuth direction of the light emitted by the light emitter by controlling multiple phase control elements; control a light source to generate light of a second wavelength; provide the light of the second wavelength generated by the light source to the resonator; adjust the phase of the light traveling along the resonator by controlling a phase modulator so that the resonant wavelength of the resonator matches the second wavelength; and while providing the light of the second wavelength generated by the light source to the light emitter, control the azimuth direction of the light emitted by the light emitter by controlling multiple phase control elements.

[0028] The optical transmitter and optical receiver can be combined into a single optical transceiver.

[0029] The LiDAR device may further include: a first waveguide disposed between a light source and an optical transceiver; a second waveguide disposed between a light source and a resonator; a third waveguide disposed between the optical transceiver and the resonator; an optical switch configured to, based on processor control, provide light generated by the light source to the first waveguide or to the second waveguide; and an optical coupler disposed on the first waveguide, wherein an end of the third waveguide is connected to the optical coupler, and the optical coupler is configured to transmit light received from the optical transceiver to the third waveguide.

[0030] The LiDAR device may further include: an optical circulator configured to output light incident on a first port of the optical circulator to a second port of the optical circulator, and to output light incident on the second port of the optical circulator to a third port of the optical circulator; a first waveguide connected between the light source and the first port of the optical circulator; an optical coupler disposed on the first waveguide; a second waveguide connected between a resonator and the optical coupler; and a third waveguide connected between the third port of the optical circulator and the resonator, wherein an optical transceiver is connected to the second port of the optical circulator.

[0031] According to one aspect of an example embodiment, a light detection and ranging (LiDAR) device is provided, comprising: a light source configured to generate light; a light emitter configured to emit the light generated by the light source to an exterior of the LiDAR device; a light receiver configured to receive light from an exterior of the LiDAR device; a resonant photodetector configured to selectively amplify and detect light received by the light receiver having a wavelength identical to that of the light generated by the light source; and a processor configured to control the light source and the resonant photodetector, wherein the resonant photodetector includes: a resonator; a phase modulator disposed on the resonator and configured to control the phase of light traveling along the resonator based on the processor's control; a first photodetector configured to detect the intensity of light traveling along the resonator; a first waveguide disposed between the light source and the light emitter; a second waveguide disposed between the light source and the resonator; a third waveguide disposed between the light receiver and the resonator; and an optical switch configured to be connected to either the first waveguide or the second waveguide. Attached Figure Description

[0032] The above and / or other aspects, features, and advantages of the exemplary embodiments will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0033] Figure 1 This is a schematic block diagram illustrating the configuration of a LiDAR device according to an example embodiment;

[0034] Figure 2A and Figure 2B It is shown Figure 1 A schematic block diagram illustrating the operation of a LiDAR device;

[0035] Figure 3 It is shown by Figure 1 A graph showing the distribution of signals detected by a LiDAR device;

[0036] Figure 4 It is shown Figure 1 A schematic diagram of another configuration of the resonant photodetector in a LiDAR device;

[0037] Figure 5 This is a schematic block diagram illustrating the configuration of a LiDAR device according to another example embodiment;

[0038] Figure 6 This is a schematic block diagram illustrating the configuration of a LiDAR device according to another example embodiment;

[0039] Figure 7 This is a schematic block diagram illustrating the configuration of a LiDAR device according to another example embodiment;

[0040] Figure 8 It is shown Figure 7A diagram showing the example resonance characteristics of each of the first and second resonators in a LiDAR device and a resonant photodetector.

[0041] Figure 9 It is shown Figure 7 A schematic diagram of another configuration of the resonant photodetector in a LiDAR device;

[0042] Figure 10 This is a schematic block diagram illustrating the configuration of a LiDAR device according to another example embodiment;

[0043] Figure 11 It is a graph showing the frequency components of the transmitted light and the frequency components of the received light in the frequency-modulated continuous wave (FMCW) method.

[0044] Figure 12 This is a schematic block diagram illustrating the configuration of a LiDAR device according to another example embodiment;

[0045] Figure 13 This is a schematic block diagram illustrating the configuration of a LiDAR device according to another example embodiment;

[0046] Figure 14 This is a schematic block diagram illustrating the configuration of a LiDAR device according to another example embodiment;

[0047] Figure 15 This is a schematic perspective view of the configuration of an OPA device according to an example embodiment;

[0048] Figure 16 It includes Figure 15 A schematic block diagram of the configuration of the LiDAR device in the OPA equipment;

[0049] Figure 17 It is by Figure 16 A diagram showing the distribution of the signal light emitted by the LiDAR device;

[0050] Figure 18 yes Figure 16 A diagram of the driving method for a LiDAR device;

[0051] Figure 19 This is a schematic block diagram of the configuration of a LiDAR device according to another example embodiment; and

[0052] Figure 20 This is a schematic block diagram of the configuration of a LiDAR device according to another embodiment. Detailed Implementation

[0053] Referring now to the embodiments illustrated in the accompanying drawings, similar reference numerals throughout refer to similar elements. In this respect, the embodiments may take different forms and should not be construed as limited to the description set forth herein. Therefore, embodiments are described below only with reference to the accompanying drawings to explain various aspects. As used herein, the term “and / or” includes any and all combinations of one or more items in the associated list. Expressions such as “at least one of…” modify the entire list of elements when following a list of elements, rather than modifying individual elements in the list. For example, the expression “at least one of a, b, and c” should be understood to include only a, only b, only c, both a and b, both a and c, both b and c, or all of a, b, and c.

[0054] In the following description, an optical detection and ranging (LiDAR) device with improved signal-to-noise ratio will be described in more detail with reference to the accompanying drawings. In the drawings, similar reference numerals denote similar elements, and the dimensions of the constituent elements may be exaggerated for ease of explanation and clarity. The exemplary embodiments are capable of various modifications and can be embodied in many different forms.

[0055] It will be understood that when an element or layer is referred to as being "on" or "above" another element or layer, that element or layer may be directly on that other element or layer, or on an intermediate element or layer. Unless the context clearly indicates otherwise, the singular form is intended to include the plural form as well. It should be understood that when a component in this specification "comprises" or "includes" an element, it does not exclude other elements, but may include them, unless otherwise defined.

[0056] In this specification, the term "above" and similar descriptive terms may be applied to both the singular and plural. For the operations constituting a method, the operations may be performed in any suitable order unless the order of operations is clearly described or unless the context clearly indicates otherwise. The operations do not necessarily have to be performed in the stated order.

[0057] Furthermore, in this specification, the terms "unit" or "module" refer to a unit or module that performs at least one function or operation, and can be implemented by hardware, software, or a combination of hardware and software.

[0058] The connections or connecting elements between the components shown in the accompanying drawings illustrate functional connections and / or physical or circuit connections, and the connections or connecting elements can be represented by various alternative or additional functional connections, physical connections, or circuit connections in the actual equipment.

[0059] The use of any and all examples or exemplary language provided herein is intended only to better illustrate the inventive concept and does not limit the scope of the inventive concept, unless otherwise required.

[0060] Figure 1 This is a schematic block diagram illustrating the configuration of a LiDAR device 100 according to an example embodiment. (Refer to...) Figure 1 The LiDAR device 100 according to an example embodiment may include: a light source 110 configured to generate light having a predetermined wavelength; a light emitter 120 configured to emit light generated by the light source 110 to the outside; a light receiver 130 configured to receive light from the outside; a resonant photodetector 140 configured to selectively amplify and detect light received by the light receiver 130 having a wavelength that is the same as the wavelength of the light generated by the light source 110; and a processor 150 configured to control the operation of the light source 110 and the resonant photodetector 140.

[0061] Light source 110 can be configured to emit pulsed light at regular time intervals under the control of processor 150. Furthermore, light source 110 can be configured to emit light in the infrared band invisible to the human eye. For example, light source 110 can be configured to emit light having wavelengths selected from about 800 nm to about 2,000 nm. Light source 110 can be, for example, a pulsed laser source, but is not limited thereto. If the emission wavelength can be controlled within a tolerance range, a light-emitting diode (LED) can be used as light source 110.

[0062] The light emitter 120 can be configured to emit light generated by the light source 110 by directing the light in a specific direction according to the control of the processor 150. The light emitter 120 can be a beam steering device that sequentially radiates light to multiple forward regions. Hereinafter, the light emitted by the light emitter 120 to the outside is referred to as signal light. For example, the light emitter 120 can perform a two-dimensional (2D) scan by radiating signal light to multiple forward regions while sequentially changing the azimuth direction at a selected elevation angle, then changing the altitude angle, and then radiating signal light while again sequentially changing the azimuth direction.

[0063] The light emitter 120 may be implemented, for example, using an optical phased array (OPA) method, but the embodiments are not limited thereto. For example, the light emitter 120 may include an actuator configured to rotate the light source 110. In this case, the light emitter 120 can rotate the light source 110 to control the radiation direction of the signal light. In another example, the light emitter 120 may include: a mirror that reflects the light generated by the light source 110; and an actuator that rotates the mirror; or a microelectromechanical system (MEMS) that electromechanically controls the reflection direction of the light generated by the light source 110.

[0064] The light receiver 130 receives light reflected by the object OBJ. The light receiver 130 can receive all light coming toward the LiDAR device 100 from the outside, but can be specifically configured to receive light coming from the direction of the signal light emitted by the light emitter 120. For example, the light receiver 130 can be implemented using an optical phased array method. In another example, the light receiver 130 can be implemented as a lens array with multiple microlenses arranged in two dimensions. When the light receiver 130 is implemented as a lens array, it may further include an actuator that controls the orientation of the lens array according to the control of the processor 150.

[0065] Furthermore, the LiDAR device 100 may also include an optical system 160 configured to radiate signal light emitted by the light emitter 120 to the outside when needed. The optical system 160 can converge the signal light so that the beam diameter of the signal light emitted by the light emitter 120 does not increase with increasing distance from the light emitter 120. Additionally, the optical system 160 can converge light arriving from the outside onto the optical receiver 130. However, the optical system 160 can be omitted when the beam diameter of the signal light emitted by the light emitter 120 is sufficiently controlled.

[0066] Furthermore, the LiDAR device 100 may also include a bandpass filter 161 configured to selectively transmit only a specific band of light from the outside toward the LiDAR device 100. The bandpass filter 161 may be positioned facing the light-receiving surface of the light receiver 130 to limit the band of light incident on the light receiver 130. The passband of the bandpass filter 161 may be matched to the band of the signal light. For example, when the light source 110 emits light having a band selection from about 800 nm to about 2,000 nm, the passband of the bandpass filter 161 may be selected within the range of about 800 nm to about 2,000 nm.

[0067] The processor 150 can control the operation of the light source 110, the light emitter 120, and the light receiver 130, and extract distance or velocity information about an external object (OBJ) based on the received signal received by the resonant photodetector 140, for example, using a time-of-flight (TOF) method. The processor 150 can be implemented as, for example, a dedicated semiconductor chip, or as software that can be executed in a computer and stored in a non-transitory computer-readable recording medium. According to another example, the processor 150 can be implemented as a programmable logic controller (PLC) or a field-programmable gate array (FPGA). Furthermore, the processor 150 can be mounted on a substrate together with the light source 110, the light emitter 120, the light receiver 130, and the resonant photodetector 140, or it can be mounted on a separate substrate.

[0068] The resonant photodetector 140 can improve the signal-to-noise ratio of the LiDAR device 100 by selectively amplifying and detecting light with the same wavelength as the signal light received by the light receiver 130. Even when using the bandpass filter 161, the passband width of the bandpass filter 161 can be selected to be approximately tens of nm, taking into account the change in wavelength of the light source 110. Therefore, even when using the bandpass filter 161, external noise such as sunlight, streetlights, and headlights of other vehicles may still be incident on the resonant photodetector 140 through the light receiver 130. The resonant photodetector 140 can selectively detect only light with the same wavelength as the signal light received by the light receiver 130.

[0069] The resonant photodetector 140 may include: a resonator 141; a phase modulator 142 disposed on the resonator 141 and configured to control the phase of light traveling along the resonator 141 based on the control of the processor 150; and a photodetector 143 capable of detecting the intensity of light traveling along the resonator 141.

[0070] Resonator 141 can be, for example, a closed-curve waveguide resonator. Figure 1 In this design, resonator 141 has a ring shape, but its shape is not limited to this and can have any other shape, such as elliptical or polygonal, as long as it has a closed-curve structure. The resonant wavelength of resonator 141 can be determined by the optical length of the closed-curve waveguide. The optical length of the closed-curve waveguide can be expressed as the product of the physical length of the closed-curve waveguide and its average refractive index.

[0071] The wavelength of the light generated by the light source 110 can be changed as needed based on the control of the processor 150, or it can be changed by external environmental variables (e.g., temperature). The phase modulator 142 can, based on the control of the processor 150, match the resonant wavelength of the resonator 141 to the wavelength of the light generated by the light source 110. For example, when the phase of the light traveling along the resonator 141 changes, it has the effect of changing the length of the closed-circuit waveguide, thus changing the resonant wavelength of the resonator 141. When the phase delay of the light increases, the length of the closed-circuit waveguide increases, thus increasing the resonant wavelength of the resonator 141. However, when the phase delay of the light decreases, the length of the closed-circuit waveguide decreases, thus decreasing the resonant wavelength of the resonator 141. Therefore, the phase modulator 142 can be configured on the resonator 141 to control the resonant wavelength of the resonator 141 by controlling the phase of the light traveling along the resonator 141.

[0072] Phase modulator 142 can change the temperature of the waveguide or change the concentration of charge carriers (e.g., electrons or holes). For example, in the temperature-changing method, the refractive index of the waveguide can be changed by altering the temperature around the waveguide, thereby controlling the phase of the light. Furthermore, in the charge carrier concentration-changing method, the refractive index of the waveguide can be changed by altering the charge carrier concentration by arranging diode junctions around the center of the waveguide, thereby controlling the phase of the light.

[0073] The photodetector 143 can detect the intensity of light traveling along the resonator 141. When the photodetector 143 absorbs all the light traveling along the resonator 141, no resonance occurs in the resonator 141. Therefore, the photodetector 143 can only absorb and detect a portion of the light traveling along the resonator 141, and allow the remaining light to pass through the resonator 141 to travel along it. The intensity of the light detected by the photodetector 143 can be the intensity of light corresponding to the resonant wavelength of the resonator 141. Therefore, the photodetector 143 measures the intensity of light having the same wavelength as the light generated by the light source 110.

[0074] In addition, the LiDAR device 100 may also include: a first waveguide 102 between the light source 110 and the light emitter 120; a second waveguide 103 between the light source 110 and the resonator 141; a third waveguide 104 between the light receiver 130 and the resonator 141; and an optical switch 101 configured to provide light generated by the light source 110 to either the first waveguide 102 or the second waveguide 103 according to the control of the processor 150.

[0075] The optical switch 101, the first waveguide 102, the second waveguide 103, and the third waveguide 104 can be mounted on the same substrate together with the resonant photodetector 140, the optical transmitter 120, and the optical receiver 130, but are not limited thereto. For example, the first waveguide 102, the second waveguide 103, and the third waveguide 104 can all include optical fibers, and the optical switch 101, the resonant photodetector 140, the optical transmitter 120, and the optical receiver 130 can be respectively fixed inside the housing of the LiDAR device 100.

[0076] The optical switch 101 can be a component that changes the optical path according to an electrical signal. For example, the optical switch 101 can be implemented in various ways, such as a Mach-Zehnder interferometer switch, a thermal heater, or a combination thereof.

[0077] The first end of the first waveguide 102 is connected to the optical switch 101, and the second end opposite to the first end can be connected to the input port of the optical transmitter 120. When the optical switch 101 provides light generated by the light source 110 to the first waveguide 102 according to the control of the processor 150, the light generated by the light source 110 is sent to the optical transmitter 120 along the first waveguide 102.

[0078] Furthermore, the first end of the second waveguide 103 is connected to the optical switch 101, and a portion of the second waveguide 103, including a second end opposite to the first end, is positioned adjacent to the resonator 141. A portion of the second waveguide 103 is arranged in a direction parallel to the tangential direction of the resonator 141, but does not physically contact the resonator 141. For example, the shortest distance between the resonator 141 and the second waveguide 103 can be greater than 0 and less than 5 times the width of the second waveguide 103. Moreover, the shortest distance between the resonator 141 and the second waveguide 103 can be less than twice the width of the second waveguide 103, for example, 0.5 to 1 times the width of the second waveguide 103. Light traveling along the second waveguide 103 towards the second end of the second waveguide 103 can then be transmitted from the second waveguide 103 to the resonator 141 without affecting the resonant wavelength of the resonator 141. When the optical switch 101 provides light generated by the light source 110 to the second waveguide 103 according to the control of the processor 150, the light generated by the light source 110 is provided to the resonator 141 along the second waveguide 103.

[0079] The first end of the third waveguide 104 is connected to the optical receiver 130, and a portion of the third waveguide 104, including the second end opposite to the first end, is adjacent to the resonator 141. A portion of the third waveguide 104 is arranged in a direction parallel to the tangent direction of the resonator 141, but does not physically contact the resonator 141. For example, the shortest distance between the resonator 141 and the third waveguide 104 can be greater than 0 and less than 5 times the width of the third waveguide 104. Furthermore, the shortest distance between the resonator 141 and the third waveguide 104 can be less than twice the width of the third waveguide 104, for example, 0.5 to 1 times the width of the third waveguide 104. Then, the third waveguide 104 can remain unaffected by the resonant wavelength of the resonator 141, and light incident on the first end of the third waveguide 104 via the optical receiver 130 can be transmitted to the resonator 141 as it travels along the third waveguide 104 toward the second end. The third waveguide 104 may be positioned on the opposite side of the second waveguide 103, with the resonator 141 positioned between them, but is not limited thereto.

[0080] In the LiDAR device 100 with the above-described structure, before providing light generated by the light source 110 to the light emitter 120 for emission to the outside, light is first provided to the resonator 141 so that the resonant wavelength of the resonator 141 matches the wavelength of the light generated by the light source 110. Thereafter, light is emitted to the outside by providing light to the light emitter 120, and in the light received by the light receiver 130, only the signal light corresponding to the resonant wavelength of the resonator 141 can be selectively amplified and detected. For example, Figure 2A and Figure 2B It is shown Figure 1 A schematic block diagram of the operation of the LiDAR device 100.

[0081] first, Figure 2A The process of tuning the resonant wavelength of resonator 141 to match the wavelength of light generated by light source 110 is shown. (Refer to...) Figure 2A The processor 150 can control the optical switch 101 to connect the light source 110 to the second waveguide 103. Then, the processor 150 turns on the light source 110 to generate light. At this time, the processor 150 can control the light source 110 to control the wavelength of the light generated by the light source 110. The light generated by the light source 110 can be sent to the resonator 141 via the second waveguide 103 and resonate in the resonator 141. The processor 150 can control the phase modulator 142 by monitoring the output of the photodetector 143 to gradually change the phase of the light traveling along the resonator 141. The process of controlling the phase delay through the phase modulator 142 can be repeated until the output of the photodetector 143 is maximized.

[0082] While controlling the phase of the light traveling along the resonator 141 via the phase modulator 142, the processor 150 can determine that the resonant wavelength of the resonator 141 matches the wavelength of the light generated by the light source 110 when the intensity of the light detected by the photodetector 143 reaches its maximum value. In this way, after determining the resonant wavelength of the resonator 141, the processor 150 can terminate... Figure 2A The tuning mode shown is such that the wavelength of the light source 110 and the phase delay according to the phase tuner 142, determined in the tuning mode, can be fixed as constants. If necessary, the processor 150 can store the control conditions determined in the tuning mode in memory.

[0083] Then, processor 150 executes signal detection mode. For example, as Figure 2B As shown, processor 150 can control optical switch 101 to connect light source 110 to first waveguide 102. The light generated by light source 110 can then be transmitted to light emitter 120 via first waveguide 102. Processor 150 can control light emitter 120 to radiate light sequentially or randomly to multiple regions. In signal detection mode, processor 150 can maintain the wavelength of light source 110 determined in tuning mode and the phase delay according to phase modulator 142.

[0084] Light incident on the optical receiver 130 from the outside can travel along the third waveguide 104. Of the light traveling along the third waveguide 104, only light with wavelengths that satisfy the resonance condition of the resonator 141 can resonate in the resonator 141 and be detected by the photodetector 143. Light with wavelengths that satisfy the resonance condition of the resonator 141 may include not only light with wavelengths that perfectly match the wavelength of the signal light, but also light with multiple wavelengths corresponding to integer multiples of the optical length of the closed-curve waveguide of the resonator 141.

[0085] For example, Figure 3 It is shown by Figure 1 A graph showing the distribution of the signal detected by the LiDAR device 100. (Refer to...) Figure 3 External noise and signal light entering through the optical receiver 130 are distributed over a wide wavelength range of at least tens of nm or more. Most of the external noise is a component that does not precisely match the resonant wavelength of the resonator 141. Therefore, the signal light component entering the resonator 141 is amplified in the closed-loop waveguide, and the noise component is output to the second end of the third waveguide 104 and disappears through scattering in the circuit board on which the third waveguide 104 is mounted or in the chip that includes the third waveguide 104.

[0086] Among the external noise, only the component that matches the resonant wavelength of resonator 141 is detected by photodetector 143 along with the signal light. For example, in Figure 3 The diagram shows multiple peaks corresponding to the resonant wavelength of resonator 141 as an example. Figure 3 As shown in the graph, the photodetector 143 can detect noise with a width of approximately 0.01 nm based on the full bandwidth at half-maximum at approximately 1 nm per period. Therefore, assuming that the external noise and signal light entering through the photoreceiver 130 include light of uniform intensity across all wavelengths, only about 1 / 100 of the external noise can be detected by the photodetector 143, and the signal-to-noise ratio of the LiDAR device 100 can be improved due to the reduced noise. Because Figure 3 The period and width of the peak shown can be determined by various design factors (e.g., the length of the closed-curve waveguide of resonator 141, the light loss in resonator 141, the spacing with the third waveguide 104, etc.), so the figures described above are merely examples.

[0087] Due to the resonance phenomenon of resonator 141, the intensity of light incident on photodetector 143, which is optically connected to resonator 141, is amplified by tens of times compared to the actual intensity of light incident on photoreceiver 130. Therefore, the same effect as improving the sensitivity of photodetector 143 can be achieved. Because of this effect, the signal-to-noise ratio of LiDAR device 100 can be improved. Therefore, even if... Figure 1 The bandpass filter 161 shown can also achieve a high signal-to-noise ratio.

[0088] As described above, the photodetector 143 may not absorb all the light traveling along the resonator 141, but may only absorb and detect a portion of the light. These conditions allow for the use of a silicon photodetector. Ideally, a silicon crystal absorbs visible light but not light in the infrared wavelength range. However, infrared absorption via two-photon absorption can be observed due to lattice defects in and above the silicon surface. The photocurrent generated via the two-photon absorption mechanism is typically about 5 mA / W, which is very weak. However, in the case of the LiDAR device 100 according to the example embodiment, a response of about 0.1 A / W can be obtained by coupling a silicon detector to the resonator 141. This is a response similar to that of photodetectors using germanium (Ge) or III-V compound semiconductors for the infrared wavelength range.

[0089] Therefore, a silicon detector can be used as a photodetector 143 for detecting signals in the infrared wavelength range. When using a silicon detector, only a portion of the light can be absorbed to a degree that maintains the resonance phenomenon in the resonator 141. Furthermore, by being coupled to the resonator 141, the silicon detector can achieve performance similar to infrared detectors using other semiconductor materials. When a silicon detector is used as a photodetector 143, Figure 1 The light emitter 120, light receiver 130 and resonant photodetector 140 shown can be implemented using current complementary metal-oxide-semiconductor (CMOS) manufacturing processes, thus greatly reducing the production cost of the LiDAR device 100.

[0090] exist Figure 1 The image depicts a photodetector 143 positioned on a closed-loop waveguide of a resonator 141, but is not limited to this. For example, Figure 4 Showing according to an example embodiment Figure 1 Another structure of the resonant photodetector 140a of the LiDAR device 100. (See reference...) Figure 4 The resonant photodetector 140a may include: an optical coupler 144 disposed on the closed-curve waveguide of the resonator 141; and a photodetector 143 connected to the optical coupler 144. The optical coupler 144 may provide a portion of the light traveling in the resonator 141 to the photodetector 143.

[0091] Figure 5 This is a schematic block diagram illustrating the configuration of a LiDAR device 100a according to another example embodiment. (Refer to...) Figure 5The LiDAR device 100a may also include a temperature sensor 151. The temperature sensor 151 may be arranged to measure the ambient temperature around the LiDAR device 100a, particularly the temperature of the light source 110. The wavelength of the light generated by the light source 110 can typically be greatly affected by temperature. The processor 150 may include a memory configured to store the relationship between the temperature of the light source 110 and the wavelength of the light.

[0092] Processor 150 can execute Figure 2A While the tuning mode is being displayed, the temperature measured by temperature sensor 151 is stored in the memory. Furthermore, during execution... Figure 2B While in the signal detection mode, the processor 150 can monitor the temperature of the light source 110 as measured by the temperature sensor 151. If the temperature measured by the temperature sensor 151 during the signal detection mode is significantly different from the temperature stored in the memory, the processor 150 can temporarily stop the signal detection mode and execute the tuning mode again. For example, if the wavelength of the light generated by the light source 110, calculated based on the temperature measured during the tuning mode, is insufficient to satisfy the resonance condition of the resonator 141, the processor 150 can stop the signal detection mode and execute the tuning mode. For example, if the wavelength of the light generated by the light source 110 changes by about 1 nm or more, the processor 150 can execute the tuning mode again. In this way, the processor 150 can match the resonant wavelength of the resonator 141 with the changed wavelength of the light generated by the light source 110 in real time.

[0093] Figure 6 This is a schematic block diagram illustrating the configuration of a LiDAR device 100b according to another example embodiment. (Refer to...) Figure 6 The LiDAR device 100b may further include a photodetector 152 located at the second end of the third waveguide 104. As described above, in the light received by the photoreceiver 130, the signal light component is amplified in the resonator 141, and the noise component travels towards the second end of the third waveguide 104. Therefore, the photodetector 152 located at the second end of the third waveguide 104 can measure the intensity of external noise. The wavelength distribution of the external noise can change according to external conditions (e.g., daytime, nighttime, tunnel, weather, etc.). The processor 150 can predict the external state based on the wavelength distribution of the external noise provided by the photodetector 152 and provide external information to the user.

[0094] Figure 7 This is a schematic block diagram illustrating the configuration of a LiDAR device 100c according to another example embodiment. (Refer to...) Figure 7The LiDAR device 100c may include: a resonant photodetector 140b, comprising at least two resonators having different optical path lengths and being optically connected to each other. For example, the resonant photodetector 140b may include: a first resonator 141a having a first optical path length; a first phase modulator 142a disposed on the first resonator 141a to control the phase of light traveling along the first resonator 141a; a first photodetector 143a for detecting the intensity of light traveling along the first resonator 141a; a second resonator 141b having a second optical path length different from the first optical path length; a second phase modulator 142b disposed on the second resonator 141b to control the phase of light traveling along the second resonator 141b; and a second photodetector 143b for detecting the intensity of light traveling along the second resonator 141b.

[0095] The first resonator 141a and the second resonator 141b can be, for example, closed-curve waveguide resonators. Figure 7 As an example, the diagram depicts a first resonator 141a as a closed-loop waveguide with a first diameter R1, and a second resonator 141b as a closed-loop waveguide with a second diameter R2, which is different from the first diameter R1. However, the closed-loop waveguides of the first resonator 141a and the second resonator 141b are not necessarily toroidal; they can be closed-loop waveguides with various shapes and different optical path lengths. Furthermore, the closed-loop waveguides of the first resonator 141a and the second resonator 141b can have different shapes from each other.

[0096] A second waveguide 103, optically connected to the optical switch 101, is arranged to transmit light generated by the light source 110 to the first resonator 141a. A third waveguide 104, optically connected to the optical receiver 130, is arranged to transmit light that has entered the optical receiver 130 to the second resonator 141b. For example, the second waveguide 103 is arranged near the first resonator 141a in a direction parallel to the tangent direction of the first resonator 141a, and the third waveguide 104 may be arranged near the second resonator 141b in a direction parallel to the tangent direction of the second resonator 141b.

[0097] The first resonator 141a and the second resonator 141b can be optically connected to each other. For example, the resonant photodetector 140b may further include a fourth waveguide 145 connected between the first resonator 141a and the second resonator 141b. Light traveling along the first resonator 141a can be transmitted to the second resonator 141b through the fourth waveguide 145, and light traveling along the second resonator 141b can be transmitted to the first resonator 141a through the fourth waveguide 145. Therefore, the light provided to the first resonator 141a through the second waveguide 102 and the light provided to the second resonator 141b through the third waveguide 104 can travel along the first resonator 141a and the second resonator 141b in an "8" shape.

[0098] When the optical path length of a closed-circuit waveguide changes, the resonant wavelength of the resonator changes, and the spacing between the resonant wavelengths (i.e., the resonant period) also changes. When two closed-circuit waveguides are connected in series, a signal can only be detected if the resonance conditions of both closed-circuit waveguides are met. Therefore, external noise detected along with the signal is limited to wavelengths that simultaneously satisfy the resonance conditions of both closed-circuit waveguides, thus achieving the effect of increasing the resonant period.

[0099] For example, Figure 8 It is shown Figure 7 A graph showing the example resonance characteristics of each of the first resonator 141a and the second resonator 141b in the LiDAR device 100c, and the final resonance characteristics of the resonant photodetector 140b. The resonant period of the resonator is proportional to the derivative of the optical path length, and the resonant period decreases as the optical path length increases. Figure 8 In this context, it is assumed that the first resonator 141a and the second resonator 141b are closed-loop waveguides with diameters R1 and R2, respectively. (Refer to...) Figure 8 While the resonant periods of each of the first resonator 141a and the second resonator 141b are relatively short, the final resonant period of the resonant photodetector 140b, in which the first resonator 141a and the second resonator 141b are connected in series, is significantly increased. For example, the final resonant period of the resonant photodetector 140b can be equal to the least common multiple of the resonant periods of the first resonator 141a and the second resonator 141b. Therefore, the external noise detected by the first photodetector 143a and the second photodetector 143b can be further reduced.

[0100] When using two resonators, the tuning modes can be executed sequentially, one after the other. For example, processor 150 first controls the phase delay via a first phase modulator 142a until the intensity of the light measured by the first photodetector 143a is maximized. In this way, the resonant wavelength of the first resonator 141a is matched with the wavelength of the light generated by the light source 110. When the intensity of the light measured by the first photodetector 143a is maximized, processor 150 then controls the phase delay via a second phase modulator 142b until the intensity of the light measured by the second photodetector 143b is maximized. In this way, the resonant wavelength of the second resonator 141b is matched with the wavelength of the light generated by the light source 110.

[0101] After determining the resonant wavelengths of the first resonator 141a and the second resonator 141b, the processor 150 provides light generated by the light source 110 to the light emitter 120 to execute a signal detection mode. In the signal detection mode, the processor 150 can use both the signal detected by the first photodetector 143a and the signal detected by the second photodetector 143b to calculate information about an external object. Using two photodetectors can improve the accuracy and precision in both the tuning mode and the signal detection mode.

[0102] exist Figure 7 The image depicts a first resonator 141a and a second resonator 141b connected in series via a fourth waveguide 145, but the embodiment is not limited to this. For example, Figure 9 Show Figure 7 Another structure of the resonant photodetector 140c in the LiDAR device 100c. (Refer to...) Figure 9 The resonant photodetector 140c may include a first resonator 141a and a second resonator 141b adjacent to each other without a fourth waveguide 145. The first resonator 141a and the second resonator 141b are not in physical contact with each other, and the shortest distance between the first resonator 141a and the second resonator 141b can, for example, be greater than 0 and less than 5 times the width of the closed curved waveguide. Furthermore, the shortest distance between the first resonator 141a and the second resonator 141b can be less than twice the width of the closed curved waveguide, for example, 0.5 to 1 times the width of the closed curved waveguide. The remaining configuration of the resonant photodetector 140c can be... Figure 7 The rest of the configuration of the resonant photodetector 140b shown is the same.

[0103] Figure 10 This is a schematic block diagram illustrating the configuration of a LiDAR device 100d according to another example embodiment. (Refer to...) Figure 10The LiDAR device 100d may also include an optical coupler 105 on the first waveguide 102. Therefore, the optical coupler 105 can be positioned in the optical path between the optical switch 101 and the optical transmitter 120. Furthermore, a first end of the second waveguide 103 of the LiDAR device 100d can be connected to the optical switch 101, and a second end extends to the optical coupler 105. The portion of the second waveguide 103 between the first and second ends is adjacent to the resonator 141 and runs along the tangential direction of the resonator 141.

[0104] According to an example embodiment, a portion of the light generated by the light source 110 and provided to the light emitter 120 via the first waveguide 102 can be provided to the resonator 141 via the optical coupler 105 and the second waveguide 103. Therefore, in signal detection mode, the light received by the optical receiver 130 and the light generated by the light source 110 can be provided together to the resonator 141. In this case, the signal measured by the photodetector 143 can be a signal of interference light formed by the interference between the received light received by the optical receiver 130 and the emitted light generated by the light source 110.

[0105] Then, processor 150 can analyze the frequency of the received signal using a frequency-modulated continuous wave (FMCW) method and calculate information about the object. For example, Figure 11 This is a graph showing the frequency components of the emitted and received light in the triangular FMCW method. Figure 11 In the diagram, the vertical axis represents frequency and the horizontal axis represents time. For example... Figure 11 As shown, the curves of the emitted and received light represent a triangle, where the frequency increases linearly with time and then decreases linearly. There is a time delay Δt between the peak frequency of the emitted light and the peak frequency of the received light. According to the FMCW method, using the signal of the interfering light measured by the photodetector 143, the processor 150 can calculate the time delay Δt between the peak frequency of the emitted and received light, and through this calculation, the distance information and relative velocity information to the object can be calculated more accurately. Figure 11 Although the triangular FMCW method is used as an example, the linear FMCW method can also be used.

[0106] In the above example embodiment, it has been described that the light source 110 is a pulsed light source, and the processor 150 calculates information about the object in front using a time-of-flight (TOF) method. However, in order to use in Figure 10 In the example embodiment of the FMCW method shown, the light source 110 can be a continuous wave light source that oscillates continuously and generates, for example, continuous light with a sinusoidal wave-like structure. Furthermore, the processor 150 can control the light source 110 to generate light such as… Figure 11The frequency-modulated light is shown. Even when using the FMCW method, the wavelength change of the frequency-modulated light can be very small, for example, about 0.006 nm. Therefore, both the minimum and maximum wavelengths of the frequency-modulated light can satisfy the resonance condition of resonator 141.

[0107] Figure 12 This is a schematic block diagram illustrating the configuration of a LiDAR device 100e according to another example embodiment. (Refer to...) Figure 12 The LiDAR device 100e may not include the optical switch 101, but instead includes: a first waveguide 102 between the light source 110 and the light emitter 120; an optical coupler 105 on the first waveguide 102; and a second waveguide 103 between the optical coupler 105 and the resonator 141. For example, a first end of the first waveguide 102 may be directly connected to the light source 110, and a second end may be directly connected to the light emitter 120. Furthermore, a first end of the second waveguide 103 is connected to the optical coupler 105, and a second end of the second waveguide may pass near the resonator 141 in a direction parallel to the tangent direction of the resonator 141.

[0108] exist Figure 12 In the illustrated example embodiment, processor 150 can switch between tuning mode and signal detection mode without optical switching. In tuning mode, a portion of the light generated by light source 110 can be provided to resonator 141 via optical coupler 105 and second waveguide 103. In tuning mode, processor 120 can stop the operation of light emitter 120. Furthermore, in signal detection mode, not only can the light received by light receiver 130 be provided to resonator 141, but also the light generated by light source 110 can be provided to resonator 141. In this case, the signal measured by photodetector 143 can be a signal of interference light formed by the interference between the received light received by light receiver 130 and the emitted light generated by light source 110. Processor 150 can calculate information about the object by analyzing the frequency of the received signal using the FMCW method.

[0109] Figure 13 This is a schematic block diagram illustrating the configuration of a LiDAR device 100f according to another exemplary embodiment. Except for the different direction of light travel within the resonator 141, Figure 13 The configuration of the LiDAR device 100f shown can be compared with... Figure 12 The configuration of the LiDAR device 100e shown is similar. For example, in Figure 12 In the case of the LiDAR device 100e shown, in the resonator 141, the emitted light travels counterclockwise, and the received light travels clockwise. Figure 13In the case of the LiDAR device 100f shown, within the resonator 141, the emitted light travels clockwise and the received light travels counterclockwise. Therefore, in Figure 13 In the LiDAR device 100f, the second waveguide 103 passes through the vicinity of the resonator 141 in a direction parallel to the tangent direction of the resonator 141 after being bent 180 degrees. Furthermore, the third waveguide 104 passes through the vicinity of the resonator 141 in a direction parallel to the tangent direction of the resonator 141 after being bent 180 degrees.

[0110] Although Figure 13 The illustration depicts both the second waveguide 103 and the third waveguide 104 being bent by 180 degrees, but the embodiment is not limited to this. For example, only the second waveguide 103 or only the third waveguide 104 may be bent by 180 degrees. When only one of the second waveguide 103 and the third waveguide 104 is bent by 180 degrees, the emitted light and the received light can travel in the same direction within the resonator 141. Even if the emitted light and the received light travel in the same direction within the resonator 141, interference signals between the emitted light and the received light may still occur.

[0111] According to the example embodiment, the resonator of the resonant photodetector has been described as a closed-curve waveguide resonator, but the embodiment is not limited thereto. For example, Figure 14 This is a schematic block diagram illustrating the configuration of a LiDAR device 100g according to another example embodiment. (Refer to...) Figure 14 The resonant photodetector 140d of the LiDAR device 100g may include a ring mirror resonator 141c. The ring mirror resonator 141c may include a first ring mirror 146 and a second ring mirror 147 formed on the waveguide.

[0112] The first ring mirror 146 and the second ring mirror 147 can be configured such that portions of the waveguide are folded into a ring, bringing the portions of the waveguide relatively close to each other. Partial reflection and partial transmission occur in the narrow neck portions of the first ring mirror 146 and the second ring mirror 147 (where some portions of the waveguide are relatively close to each other). Therefore, an optical resonance effect occurs between the first ring mirror 146 and the second ring mirror 147, so the first ring mirror 146 and the second ring mirror 147 can be used as resonators. A phase modulator 142 and a photodetector 143 can be disposed on the waveguide located between the first ring mirror 146 and the second ring mirror 147 where resonance occurs.

[0113] exist Figure 14In the example embodiment shown, the second waveguide 103, the ring mirror resonator 141c, and the third waveguide 104 can be integrally configured using a single waveguide. For example, a waveguide can extend from the optical switch 101 to the optical receiver 130, and the first ring mirror 146 and the second ring mirror 147 can be formed in the middle of the waveguide. Figure 14 In the diagram, the waveguide between the optical switch 101 and the first ring mirror 146 is designated as the second waveguide 103, and the waveguide between the optical receiver 130 and the second ring mirror 147 is designated as the third waveguide 104.

[0114] When the light emitter 120 and light receiver 130 are implemented using the OPA method, they can be integrated into a single chip. Furthermore, the light emitter 120, light receiver 130, and resonant photodetector 140 can be integrated into a single chip, or the light source 110, light emitter 120, light receiver 130, and resonant photodetector 140 can be integrated into a single chip. Therefore, when the light emitter 120 and light receiver 130 are implemented using the OPA method, the LiDAR device can be minimized.

[0115] For example, Figure 15 This is a schematic perspective view of the configuration of the OPA device 200 according to an example embodiment. (Refer to...) Figure 15 The OPA device 200 may include a substrate 201, a light source 110 on the substrate 201, a beam-splitting region 200A, a phased array region 200B, an amplification region 200C, and a transmission region 200D. The light source 110, beam-splitting region 200A, phased array region 200B, amplification region 200C, and transmission region 200D may be arranged along a first direction DR1. The OPA device 200 may include a plurality of optical waveguides 211 configured to sequentially transmit light generated by the light source 110 to the beam-splitting region 200A, phased array region 200B, amplification region 200C, and transmission region 200D. The light generated by the light source 110 can travel along the first direction DR1 through the optical waveguides 211. Figure 15 As an example, the light source 110 is depicted as being integrally formed with the OPA device 200, but the light source 110 can be manufactured separately from the OPA device 200.

[0116] The beam splitting region 200A may include multiple beam splitters 220. Multiple beam splitters 220 can split a beam of light traveling along an optical waveguide 211 into multiple beams. For this purpose, one optical waveguide 211 may be connected to the input terminal of each beam splitter 220, and multiple optical waveguides 211 may be connected to the output terminal of each beam splitter 220. As an example, in Figure 15The diagram shows multiple beam splitters 220 that split a beam of light into two beams. Light generated by light source 110 can be split into multiple beams within a beam splitting region 200A. Each split beam travels along a plurality of optical waveguides 211. Figure 15 The image depicts light generated by light source 110 being split into eight beams in beam splitting region 200A, but the embodiment is not limited to this.

[0117] Phased region 200B may include multiple phased elements 230, each disposed within multiple optical waveguides 211. For example, the multiple phased elements 230 may be arranged in a second direction DR2 perpendicular to the first direction DR1. Multiple beams of light separated in beam-splitting region 200A may be provided to the multiple phased elements 230 respectively. Phased elements 230 may have electrically controllable variable refractive indices. The phase of light passing through phased elements 230 can be determined based on the refractive index of the phased elements 230. The phases of the separated beams can be independently controlled by each phased element 230.

[0118] The amplification region 200C may include a plurality of optical amplifiers 240, each disposed in a plurality of optical waveguides 211. The plurality of optical amplifiers 240 may be arranged in a second direction DR2 perpendicular to the first direction DR1. The optical amplifiers 240 can increase the intensity of the optical signal. For example, each of the optical amplifiers 240 may include a semiconductor optical amplifier or an ion-doped amplifier.

[0119] The emission region 200D may include multiple grating pattern groups 250. The multiple grating pattern groups 250 may be arranged along a second direction DR2. The multiple grating pattern groups 250 may be respectively connected to multiple optical amplifiers 240. Each of the grating pattern groups 250 may respectively emit light amplified in the amplification region 200C. For this purpose, each of the grating pattern groups 250 may include multiple grating patterns 250a arranged periodically. The multiple grating patterns 250a may be arranged along a first direction DR1. The travel direction of the output light OL emitted by the grating pattern groups 250 can be determined by the phase difference between the separated beams of light determined in the phase-controlled region 200B, the gap between the grating patterns 250a, the height of the grating patterns 250a, and the width of the grating patterns 250a. For example, the travel direction of the output light OL may include: a component along the first direction DR1, a component along the second direction DR2, and a component along a third direction DR3 perpendicular to the first direction DR1 and the second direction DR2.

[0120] when Figure 15When the OPA device 200 shown is used as a light emitter, the processor 150 can independently control multiple phase control elements 230 to control the phase of the separated multiple beams of light, thereby controlling the azimuth direction of the emitted light emitted through the grating pattern group 250. For example, the emitted light can be emitted along different azimuth directions according to the phase difference set in the multiple phase control elements 230. The elevation direction of the signal light emitted through the grating pattern group 250 can be achieved by changing the wavelength of the light source 110. For example, in the 1,310 nm band, when the wavelength is changed by 10 nm, the elevation angle changes by approximately 2°.

[0121] also, Figure 15 The OPA device 200 shown can also be used as a light receiver. In this case, the OPA device 200 can operate in reverse to the light emitter. For example, light can be input through the grating pattern group 250, and the processor 150 can pre-control the phases of the plurality of phased elements 230 to set the desired direction of light input. Light incident from the direction set by the processor 150 can produce constructive interference while passing through the plurality of phased elements 230 and can be combined into a single waveguide, thus being detected by a photodetector. However, light incident from a direction that does not match the set direction can produce destructive interference while passing through the plurality of phased elements 230 and can be combined into a single waveguide, thus not being detected by a photodetector.

[0122] Figure 16 It includes Figure 15 A schematic block diagram of the configuration of the LiDAR device 100h of the OPA device 200. Figure 16 The LiDAR device 100h shown has the same characteristics as... Figure 1 The LiDAR device 100 shown has essentially the same structure, but the difference is that the LiDAR device 100h includes components made of... Figure 15 The LiDAR device 100h comprises a light emitter 120a and a light receiver 130a, which are composed of optical phased array elements 200. Furthermore, the LiDAR device 100h may include a single substrate 121 on which a light source 110, a light emitter 120a, a light receiver 130a, and a resonant photodetector 140 are mounted together. The light emitter 120a may include multiple phased array elements 124 and multiple grating pattern groups 126, and the light receiver 130a may also include multiple phased array elements 134 and multiple grating pattern groups 136. This configuration, including the OPA device, can be applied to all LiDAR devices according to all the example embodiments described above. Figure 1 The LiDAR device 100.

[0123] The LiDAR device 100h can perform 2D scanning of a forward area using a light emitter 120a and a light receiver 130a. For example, Figure 17 It is by Figure 16 A diagram showing the distribution of the signal light emitted by the LiDAR device over 100 hours. (See diagram for example.) Figure 17 As shown, the LiDAR device 100h can operate at the first elevation angle. While keeping it fixed, for the direction from the first azimuth direction θ1 to the Nth azimuth direction θ N The area is scanned sequentially. As described above, the azimuth angle can be controlled by multiple phase control elements 124, and the elevation angle can be determined by the wavelength of the light generated by the light source 110. The processor 110 can control the light source 110 to generate light λ1 of a first wavelength, thereby emitting light along the first elevation angle direction. The light.

[0124] Then, the LiDAR device 100h can control the elevation direction to the second elevation direction. Therefore, the processor 110 can control the light source 110 to generate light λ2 of the second wavelength. Furthermore, the processor 110 can control the phased array element 124 to move from the first azimuth direction θ1 to the Nth azimuth direction θ N The scanning is performed sequentially. Since the wavelength of the light generated by the light source 110 can change whenever the elevation angle changes, the LiDAR device 100h can perform a tuning mode in this way. That is, whenever the elevation angle changes, the LiDAR device 100h can control the phase modulator 142 of the resonant photodetector 140 to match the resonant wavelength of the resonator 141 with the wavelength of the light generated by the light source 110.

[0125] For example, Figure 18 yes Figure 16 A diagram illustrating the driving method of the 100h LiDAR device. (Refer to...) Figure 18 The processor 150 can control the light source 110 to generate light λ1 of a first wavelength, thereby emitting light along the first elevation angle direction. In the tuning mode, the resonant wavelength of the resonator 141 can be matched with the first wavelength λ1 by providing light of the first wavelength λ1 to the resonator 141 and controlling the phase of the light traveling along the resonator 141 by controlling the phase modulator 142. Then, in the signal detection mode, the processor 150 can control multiple phase control elements 124 simultaneously with the first wavelength λ1 light generated by the light source 110 being provided to the light emitter 120a to move the light from the first azimuth direction θ1 to the Nth azimuth direction θ. N The azimuth direction of the light emitted by the light emitter 120a is controlled sequentially.

[0126] When targeting the first elevation angle direction When the scan is complete, the processor 150 can control the light source 110 to generate light λ2 of a second wavelength, thereby emitting light along the second elevation angle direction. In the tuning mode, the resonant wavelength of the resonator 141 can be matched with the second wavelength λ2 by providing light of the second wavelength λ2 to the resonator 141 and controlling the phase of the light traveling along the resonator 141 by controlling the phase modulator 142. Then, in the signal detection mode, the processor 150 can control multiple phase control elements 124 simultaneously with the second wavelength λ2 light generated by the light source 110 being provided to the light emitter 120a, to control the light from the first azimuth direction θ1 to the Nth azimuth direction θ... N The azimuth direction of the light emitted by the light emitter 120a is controlled sequentially.

[0127] Furthermore, when using an OPA device, the aforementioned optical transmitter 120a and optical receiver 130a can be integrated into a single optical transceiver for manufacturing. For example, Figure 19 This is a schematic block diagram illustrating the configuration of a LiDAR device according to another example embodiment. (Refer to...) Figure 19 The LiDAR device 100i may include a light source 110, an optical transceiver 125, and a resonant photodetector 140. The optical transceiver 125 includes an OPA device and can be used as both an optical transmitter and an optical receiver.

[0128] Furthermore, the LiDAR device 100i may include: a first waveguide 102 between the light source 110 and the optical transceiver 125; a second waveguide 103 between the light source 110 and the resonator 141 of the resonant photodetector 140; a third waveguide 104 between the optical transceiver 125 and the resonator 141; an optical switch 101 that, under the control of the processor 150, supplies light generated by the light source 110 to either the first waveguide 102 or the second waveguide 103; and an optical coupler 105 on the first waveguide 102. A first end of the third waveguide 104 is connected to the optical coupler 105. The optical coupler 105 can transmit light from the first waveguide 102 to the optical transceiver 125 and transmit light received by the optical transceiver 125 to the third waveguide 104.

[0129] Figure 20 This is a schematic block diagram of the configuration of a LiDAR device 100j according to another example embodiment. (Refer to...) Figure 20The LiDAR device 100j may include a light source 110, an optical transceiver 125, and a resonant photodetector 140. Furthermore, the LiDAR device 100j may include: an optical circulator 106 that outputs light incident on a first port to a second port and outputs light incident on the second port to a third port; a first waveguide 102 connected between the light source 110 and the first port of the optical circulator 106; an optical coupler 105 on the first waveguide 102; a second waveguide 103 connected between a resonator 141 and the optical coupler 105; and a third waveguide 104 connected between the resonator 141 and the third port of the optical circulator 106.

[0130] The light generated by the light source 110 can be split at the optical coupler 105 and provided to the first port of the resonator 141 and the optical circulator 106. The light provided to the first port of the optical circulator 106 can be output to the second port and sent to the optical transceiver 125. Furthermore, the light received by the optical transceiver 125 can be input to the second port of the optical circulator 106 and output to the third port of the optical circulator 106. Additionally, the light output through the third port of the optical circulator 106 can be provided to the resonator 141 through the third waveguide 104. Therefore, signal light and received light are simultaneously provided to the resonator 141, and... Figure 20 The LiDAR device 100j can, for example, calculate information about objects in front using the FMCW method.

[0131] The aforementioned LiDAR device can be mounted, for example, on a vehicle and configured to extract distance and relative speed information about vehicles near the LiDAR device. However, the LiDAR device according to the example embodiment is not necessarily limited to vehicles. For example, in addition to vehicles, the LiDAR device can also be mounted on ships, airplanes, or drones and can be used to search for and avoid obstacles in front of ships, airplanes, or drones.

[0132] It should be understood that the exemplary embodiments described herein should be considered descriptive only and not for limiting purposes. The description of features or aspects in each exemplary embodiment should typically be interpreted as other similar features or aspects that may be used in other embodiments. Although exemplary embodiments have been described with reference to the accompanying drawings, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope defined by the claims.

Claims

1. A LiDAR device for optical detection and ranging, comprising: The light source is configured to generate light; A light emitter is configured to emit light generated by the light source toward the exterior of the LiDAR device; A light receiver is configured to receive light from outside the LiDAR device; A resonant photodetector is configured to selectively amplify and detect light received by the light receiver that has the same wavelength as the light generated by the light source; as well as The processor is configured to control the light source and the resonant photodetector. The resonant photodetector includes: Resonator; A phase modulator, disposed on the resonator, and configured to control the phase of light traveling along the resonator based on the control of the processor; and A photodetector is configured to detect the intensity of light traveling along the resonator. The LiDAR device further includes: A first waveguide is disposed between the light source and the light emitter; A second waveguide is disposed between the light source and the resonator; A third waveguide is disposed between the optical receiver and the resonator; and An optical switch, configured to, based on the processor's control, supply light generated by the light source to either the first waveguide or the second waveguide. The processor is further configured as follows: Before the light generated by the light source is provided to the light emitter, the light is provided to the resonator by the light switch; By controlling the phase tuner to adjust the phase of the light traveling along the resonator, the resonant wavelength of the resonator is matched to the wavelength of the light generated by the light source; and After determining the resonant wavelength of the resonator, the light generated by the light source is provided to the light emitter, and The processor is further configured to: while adjusting the phase of the light traveling along the resonator by controlling the phase tuner, determine that the resonant wavelength of the resonator matches the wavelength of the light generated by the light source when the intensity of the light detected by the resonant photodetector reaches its maximum value.

2. The LiDAR device according to claim 1, further comprising: A temperature sensor is configured to measure the temperature of the light source. The processor is further configured as follows: Based on the temperature measured by the temperature sensor, the wavelength of the light generated by the light source is determined, and Based on the fact that the change in wavelength of the light generated by the light source exceeds a predetermined range, the phase of the light traveling along the resonator is adjusted by controlling the phase tuner so that the resonant wavelength of the resonator matches the wavelength of the light generated by the light source.

3. The LiDAR device according to claim 1, further comprising: An additional optical detector, connected to the end of the third waveguide, is configured to measure the intensity of external noise.

4. The LiDAR device according to claim 1, further comprising: Optical coupler on the first waveguide, The second waveguide extends to the optical coupler, and a portion of the light supplied to the optical transmitter through the first waveguide is supplied to the resonator through the optical coupler and the second waveguide.

5. The LiDAR device according to claim 4, wherein, The light source includes a continuous wave light source, which is configured to generate continuous wave light, and The processor is further configured as follows: Control the light source to generate frequency-modulated light, and Using the frequency modulated continuous wave (FMCW) method, extract at least one of the distance information and velocity information of the external object.

6. The LiDAR device according to claim 1, wherein, The resonator includes a first resonator and a second resonator, the first resonator and the second resonator having different optical path lengths and being optically connected to each other. The phase modulator includes: a first phase modulator disposed on the first resonator and configured to control the phase of light traveling along the first resonator based on control of the processor; and a second phase modulator disposed on the second resonator and configured to control the phase of light traveling along the second resonator based on control of the processor. The photodetector includes: a first photodetector configured to detect the intensity of light traveling along the first resonator; and a second photodetector configured to detect the intensity of light traveling along the second resonator.

7. The LiDAR device according to claim 6, wherein, The processor is also configured to: Before providing the light generated by the light source to the light emitter, the light generated by the light source is provided to the first resonator; By controlling the first phase tuner to adjust the phase of the light traveling along the first resonator, the resonant wavelength of the first resonator is matched with the wavelength of the light generated by the light source; By controlling the second phase tuner to adjust the phase of the light traveling along the second resonator, the resonant wavelength of the second resonator is matched with the wavelength of the light generated by the light source; as well as After determining the resonant wavelengths of the first resonator and the second resonator, the light generated by the light source is provided to the light emitter.

8. The LiDAR device according to claim 6, wherein, The second waveguide is disposed between the light source and the first resonator, and the third waveguide is disposed between the optical receiver and the second resonator.

9. The LiDAR device according to claim 1, wherein, The resonator includes a closed-curve waveguide resonator.

10. The LiDAR device according to claim 1, wherein, The resonator includes a first ring mirror and a second ring mirror disposed on the waveguide, and The phase tuner and the photodetector are disposed on the waveguide and between the first ring mirror and the second ring mirror.

11. The LiDAR device according to claim 10, wherein, The second waveguide is disposed between the light source and the first circular mirror, and the third waveguide is disposed between the optical receiver and the second circular mirror.

12. The LiDAR device according to claim 1, wherein, The optical transmitter and the optical receiver each include an optical phased array (OPA) device.

13. The LiDAR device according to claim 12, wherein, The light emitter also includes: substrate; Multiple waveguides are disposed on the substrate; Multiple beam splitters, each comprising: an input terminal connected to one of the multiple waveguides, and an output terminal connected to at least two of the multiple waveguides; Multiple phase-array elements are configured to independently control the phase of multiple beams of light separated by the multiple beam splitters; and Multiple grating pattern groups are respectively connected to the multiple phase control elements and are configured to emit multiple beams of light with controlled phase.

14. The LiDAR device according to claim 13, wherein, The light source, the light emitter, the light receiver, and the resonant photodetector are disposed on a single substrate.

15. The LiDAR device according to claim 13, wherein, The processor is also configured to: By controlling the plurality of phase-controlled elements to adjust the phase of the separated light, the azimuth direction of the light emitted by the light emitter is controlled; and The elevation angle of the light emitted by the light emitter is controlled by controlling the wavelength of the light generated by the light source.

16. The LiDAR device according to claim 15, wherein, The processor is also configured to, based on a change in the elevation angle of the light emitted by the light emitter, control the phase tuner to match the resonant wavelength of the resonator with the wavelength of the light generated by the light source.

17. The LiDAR device according to claim 16, wherein, The processor is also configured to: The light source is controlled to generate light of a first wavelength; The light of the first wavelength generated by the light source is provided to the resonator; By controlling the phase tuner to adjust the phase of the light traveling along the resonator, the resonant wavelength of the resonator is matched with the first wavelength; While providing the light of the first wavelength generated by the light source to the light emitter, the azimuth direction of the light emitted by the light emitter is controlled by controlling the plurality of phase control elements; The light source is controlled to generate light of a second wavelength; The second wavelength of light generated by the light source is provided to the resonator; By controlling the phase tuner to adjust the phase of the light traveling along the resonator, the resonant wavelength of the resonator is matched with the second wavelength; as well as While providing the light of the second wavelength generated by the light source to the light emitter, the azimuth direction of the light emitted by the light emitter is controlled by controlling the plurality of phase control elements.

18. The LiDAR device according to claim 12, wherein, The optical transmitter and the optical receiver are integrated into a single optical transceiver.

19. The LiDAR device according to claim 18, further comprising: An optical coupler is disposed on the first waveguide. The first waveguide is disposed between the light source and the optical transceiver, and the third waveguide is disposed between the optical transceiver and the resonator. The third waveguide is connected at one end to the optical coupler, and the optical coupler is configured to transmit light received from the optical transceiver to the third waveguide.

20. The LiDAR device according to claim 18, further comprising: An optical circulator is configured to output light incident on a first port of the optical circulator to a second port of the optical circulator, and to output light incident on the second port of the optical circulator to a third port of the optical circulator. as well as An optical coupler is disposed on the first waveguide; The first waveguide is connected between the light source and the first port of the optical circulator. The second waveguide is connected between the resonator and the optical coupler. The third waveguide is connected between the third port of the optical circulator and the resonator, and The optical transceiver is connected to the second port of the optical circulator.

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