Waveguide structure, silicon optical chip, detection device and terminal equipment

Abstract

The utility model discloses a waveguide structure, a silicon optical chip, a detection device and terminal equipment, relates to the technical field of sensors, and is used for reducing transmission loss caused by a TPA effect of a waveguide under high optical power. The waveguide structure comprises an end face coupler, a first waveguide and a second waveguide, the first waveguide is connected to the first output end of the end face coupler, the second waveguide is connected to the second output end of the end face coupler, the input end of the end face coupler has a first spot size, and the first waveguide and the second waveguide both have a second spot size. The first spot size is larger than the second spot size. The input of the end face coupler is of a large spot size, the output of the end face coupler is of two small spot sizes, the end face coupler can directly split an input optical signal into two waveguides, the optical power in each waveguide is reduced, high optical power density is not prone to occurring in each waveguide, and the TPA effect is not prone to occurring. The problem of large transmission loss caused by the TPA effect of the waveguide under high optical power density can be solved.

Description

Technical Field

[0001] The present application relates to the field of sensor technology, and in particular to laser radar and waveguide structure and silicon photonic chip in the laser radar. The laser radar can be applied but not limited to the field of transportation control. Background Art

[0002] In the silicon photonic chip process, the Silicon-On-Insulator (SOI) process is the most mature. This process achieves dielectric isolation between components in the chip by introducing a buried oxide layer (also called an insulating layer) between the top silicon and the back substrate. Compared with silicon nitride (SiN) and programmable logic chips (PLC), SOI silicon photonic chips have the advantages of small size, doping, support for active device integration such as photodiodes (PDs), high yield, and low cost.

[0003] At present, the waveguide in SOI silicon photonic chips is called silicon optical waveguide. Due to the high refractive index of silicon, it is usually transparent to light with a wavelength exceeding 1.1μm. However, under high optical power density, two photons with a wavelength exceeding 1.1μm will be absorbed and generate carriers, which will further absorb light, resulting in increased transmission loss of silicon optical waveguide, increased temperature, and decreased reliability. This phenomenon is called the two-photon absorption (TPA) effect of silicon optical waveguide. The TPA effect of silicon optical waveguide is positively correlated with the optical power density in the silicon optical waveguide. The greater the optical power density, the stronger the TPA effect and the greater the transmission loss of the silicon optical waveguide.

[0004] Therefore, how to reduce the transmission loss caused by the TPA effect of waveguide under high optical power is a technical problem that needs to be solved urgently in the field of SOI silicon photonic chips. Utility Model Content

[0005] The present application provides a waveguide structure, a silicon photonic chip, a detection device and a terminal device, which are used to reduce the transmission loss caused by the TPA effect of the waveguide under high optical power and increase the maximum optical power that the silicon photonic chip can withstand.

[0006] In a first aspect, the present application provides a waveguide structure, including an end coupler, a first waveguide and a second waveguide, the first waveguide being connected to a first output end of the end coupler, the second waveguide being connected to a second output end of the end coupler, the input end of the end coupler inputting a first optical signal, the first output end of the end coupler outputting a second optical signal, the second output end of the end coupler outputting a third optical signal, the input end of the end coupler having a first mode spot size, the first waveguide and the second waveguide both having a second mode spot size, the first mode spot size being larger than the second mode spot size.

[0007] Based on the above waveguide structure, the input of the end coupler is a large mode spot size, and the output is two small mode spot sizes. Therefore, the end coupler can convert a large mode spot input into two small mode spot outputs. In this way, all optical power coupled into the end coupler will be divided into two waveguides, and the situation where all optical power is in one waveguide will not appear. The optical power of the optical signal transmitted in each waveguide can be reduced, making it less likely for high optical power density to appear in each waveguide. In this way, when the waveguide structure is applied to SOI silicon photonic chips, it is less likely to produce TPA effect in each waveguide, which can solve the problem of large transmission loss caused by TPA effect of waveguides in SOI silicon photonic chips under high optical power density. In addition, the above waveguide structure directly splits two optical signals through the end coupler. Compared with the prior art method of splitting two optical signals through the end coupler and a beam splitter, it can save the number of required beam splitters and reduce costs and structural complexity. Furthermore, the above waveguide structure is completely made of passive devices. Therefore, it can be directly formed through a single exposure without adding additional semiconductor process steps, nor does it require additional processes such as doping and power-on, and additional power consumption. It has the advantages of simple process, extremely simple architecture, extremely low cost, extremely high performance, and extremely high reliability.

[0008] In a possible design, both the first waveguide and the second waveguide are single-mode waveguides. A single-mode waveguide has a smaller cross-sectional size and transmits only a single mode inside, and does not have multiple modes or collision interference between multiple modes, and has a better light transmission effect.

[0009] In one possible design, the optical power of the second optical signal is equal to the optical power of the third optical signal.

[0010] Based on the above design, the end coupler can equally divide the coupled first optical signal into the second optical signal and the third optical signal. Therefore, under ideal conditions, the optical power density in each waveguide is half of the input optical power, which can effectively reduce the probability of TPA effect occurring in each waveguide.

[0011] In a possible design, the end face coupler, the first waveguide and the second waveguide are located in a transmitting component, and the transmitting component may also include other structures, mainly including the following structure one and structure two.

[0012] Structure 1, the transmitting component also includes a first beam splitter and a second beam splitter, the first beam splitter is connected between the output end of the first waveguide and at least two first transmitting ends of the chip where the waveguide structure is located, the second beam splitter is connected between the output end of the second waveguide and at least two second transmitting ends of the chip, the first beam splitter is used to split at least two first transmitting signals from the input optical signal, and the second beam splitter is used to split at least two second transmitting signals from the input optical signal, wherein at least two first transmitting signals are emitted to the scanning component through at least two first transmitting ends, at least two second transmitting signals are emitted to the scanning component through at least two second transmitting ends, and at least two first transmitting signals and at least two second transmitting signals are scanned by the scanning component to the detection space for detecting the target.

[0013] Based on the above structure 1, a transmitting component can be set in the waveguide structure, and the transmitting component emits at least four transmitting signals through at least four transmitting ends, and the at least four transmitting signals can be used to jointly measure the target in the detection space. For example, at least four transmitting signals can correspond to at least four detection channels, so that at least four areas can be detected through one scan, the scanning range of one detection becomes larger, and the detection efficiency is improved.

[0014] In an example of structure one, the waveguide structure also includes a receiving component, which is used to acquire a local oscillator signal and an echo signal, and mix the local oscillator signal and the echo signal to obtain an intermediate frequency signal, wherein the local oscillator signal is separated from an input signal, a transmitted signal or an output signal obtained from any device in the end face coupler, the first waveguide, the second waveguide, the first beam splitter or the second beam splitter, and the intermediate frequency signal is used to determine the speed and / or distance of the target.

[0015] Based on the above example, when the transmitting component includes one, the receiving component also includes one, and the local oscillator signal of the receiving component can be separated from the relevant signal of any element in the transmitting component. Therefore, the waveguide structure has high flexibility and versatility and can be adapted to various detection occasions.

[0016] In the above example, the local oscillator signal in the receiving component can be separated by any of the following separation methods 1 to 3:

[0017] In the first separation mode, the end coupler also has a third output end, and the third output end outputs a local oscillator signal, and the receiving component is connected between the third output end and the receiving end of the chip. Based on the first separation mode, the local oscillator signal can be separated from the input signal of the end coupler, and the end coupler directly splits the input optical signal into three optical signals, two of which are divided into at least four transmission signals by the beam splitter, and the other optical signal is used as the local oscillator signal to mix with the echo signal. In this way, in the case of equal power beam splitting by the beam splitter, the power of at least four transmission signals is equal, the light output of at least four detection channels is uniform, and at least four transmission signals can hit the same distance in the detection space, thereby obtaining detection results of different areas at the same distance. The detection effect under this detection mode is the best;

[0018] In the second branching mode, the second beam splitter also has another output end, the receiving component is connected between the other output end and the receiving end of the chip, and the second beam splitter is also used to split the local oscillator signal from the input optical signal, and output the local oscillator signal to the receiving component through the other output end. Based on the second branching mode, the local oscillator signal can be separated from the input signal of the second beam splitter, and the second beam splitter splits the input optical signal into at least three optical signals, at least two of which are used as at least two transmission signals, and the other optical signal is used as a local oscillator signal to be mixed with the echo signal;

[0019] In the third separation mode, the waveguide structure further includes a beam splitter element, which is coupled between the second waveguide and the input end of the receiving component. The beam splitter element is used to split the third optical signal transmitted in the second waveguide into a local oscillator signal, and output the local oscillator signal to the receiving component. Based on the third separation mode, the local oscillator signal can be separated from the signal transmitted by the second waveguide based on the beam splitter element, a part of the optical signal transmitted in the second waveguide is separated as the local oscillator signal, and the rest is split into at least two transmission signals by the second beam splitter.

[0020] In one example of the above light splitting method three, the light splitting element may be a directional coupler or a beam splitter.

[0021] Based on the above examples, the directional coupler can couple the local oscillator signal from the second waveguide in a non-contact manner, and the beam splitter can be inserted into the second waveguide to directly split the local oscillator signal. Therefore, the waveguide structure can be applied to different splitting elements, improving flexibility and versatility.

[0022] Structure 2, there are N transmitting components, N is an integer greater than or equal to 2, in this case, the waveguide structure also includes a first beam combiner and a second beam combiner, each of which has N input ends and at least two output ends; the N input ends of the first beam combiner and the second beam combiner are respectively connected to the output ends of the N first waveguides in the N transmitting components, and the at least two output ends of the first beam combiner and the at least two first transmitting ends of the chip where the waveguide structure is located; the N input ends of the second beam combiner and the second beam combiner are respectively connected to the output ends of the N second waveguides in the N transmitting components, and the at least two output ends of the second beam combiner and the second beam combiner are connected to the at least two first transmitting ends of the chip where the waveguide structure is located The output end is connected to at least two second transmitting ends of the chip; the first beam combiner and splitter is used to combine the N input optical signals into one beam and then split them into at least two first transmitting signals, and the second beam combiner and splitter is used to combine the N input optical signals into one beam and then split them into at least two second transmitting signals, wherein at least two first transmitting signals are emitted to the scanning component through at least two first transmitting ends, at least two second transmitting signals are emitted to the scanning component through at least two second transmitting ends, and at least two first transmitting signals and at least two second transmitting signals are scanned by the scanning component to the detection space for detecting the target.

[0023] Based on the above structure 2, N transmitting components can be set in the waveguide structure, and the optical signals emitted by the N transmitting components form at least four transmitting signals through two beam combiners and splitters, and the at least four transmitting signals can be used to jointly measure the target in the detection space. For example, at least four transmitting signals can correspond to at least four detection channels, so that at least four areas can be detected through one scan, the scanning range of one detection becomes larger, and the detection efficiency is improved.

[0024] In an example of Structure 2, optical signals from N transmitting components have different wavelengths and / or different polarization states.

[0025] Based on the above example, if there are different wavelengths, each transmission signal has N wavelengths, and the N wavelengths correspond to different detection distances. Therefore, each transmission signal can detect more distances, which can improve the comprehensiveness of detection. If there are different polarization states, multiple signals of the same wavelength can be used to detect the same distance to improve detection accuracy.

[0026] In an example of structure 2, the waveguide structure further includes a receiving component, which is used to obtain a local oscillator signal and an echo signal, and mix the local oscillator signal and the echo signal to obtain an intermediate frequency signal. The local oscillator signal is separated from an input signal, a transmitted signal or an output signal of any device in the end coupler of any transmitting component, the first waveguide of any transmitting component, the second waveguide of any transmitting component, the first beam combiner or the second beam combiner, and the intermediate frequency signal is used to determine the speed and / or distance of the target.

[0027] Based on the above examples, when the transmitting components include multiple components, the receiving components may include one or more components, and the local oscillator signals of the one or more receiving components can be separated from the relevant signals of the elements of any multiple transmitting components. Therefore, the waveguide structure has high flexibility and versatility and can be adapted to various detection scenarios.

[0028] In the above example, the local oscillator signal in the receiving component can be separated by any of the following separation methods 1 to 3:

[0029] In the first separation mode, there are N receiving components, and the N receiving components correspond one to one with the N transmitting components. The N end face couplers in the N transmitting components all have a third output end, and the third output end of each end face coupler is used to output a local oscillator signal. Each receiving component is connected between the third output end of the end face coupler in the corresponding transmitting component and a receiving end of the chip. Based on the first separation mode, there are N receiving components, and the local oscillator signals of the N receiving components are respectively separated from the input signals of the end face couplers of the N transmitting components. The N local oscillator signals have different wavelengths, and each local oscillator signal is a single-wavelength signal. Therefore, when mixing, the single-wavelength signal is also mixed. Moreover, in the case where the beam combiner and splitter are equal-power optical signals, at least four transmitting signals are equal-power, and at least four detection channels have uniform light output;

[0030] In the second demultiplexing mode, the second beam combiner and splitter also has another output end, and the receiving component is connected between the other output end and the receiving end of the chip. The second beam combiner and splitter is also used to split the local oscillator signal from the combined optical signal, and output the local oscillator signal to the receiving component through the other output end. Based on the second demultiplexing mode, there can be only one receiving component, and the local oscillator signal of the receiving component is separated from the input signal of any beam combiner and splitter. The local oscillator signal is a signal of N wavelengths, and the mixing operation is a single mixing of the N wavelength signal;

[0031] In the third separation method, there are N receiving components, and the waveguide structure also includes N splitting elements. The N splitting elements correspond to the N transmitting components and the N receiving components one by one. Each splitting element is coupled between the first waveguide of the corresponding transmitting component and the input end of the corresponding receiving component, or is coupled between the second waveguide of the corresponding transmitting component and the input end of the corresponding N receiving components; the N splitting elements are used to split the local oscillator signal from the optical signal transmitted by the coupled first waveguide or the second waveguide, and output the local oscillator signal to the coupled receiving component. Based on the third separation method, there are N receiving components, and the local oscillator signal of each receiving component can be separated from the signal transmitted by the waveguide of a transmitting component. The separation method can be coupled out by a directional coupler, or split by a beam splitter. The local oscillator signals of the N receiving components are all single-wavelength signals with different wavelengths.

[0032] In an example of the above structure one or structure two, the optical power of the local oscillator signal is less than the optical power of the second optical signal and the optical power of the third optical signal.

[0033] Based on this example, the local oscillator signal may have a smaller optical power to reduce the power impact on the transmit signal and increase the detection distance of the transmit power.

[0034] In an example of the above structure one or structure two, the receiving component includes a fourth beam splitter and K mixers, K is an integer greater than or equal to 2; the input end of the fourth beam splitter is used to receive the local oscillator signal, the K output ends of the fourth beam splitter are connected to the K first input ends of the K mixers, and the K second input ends of the K mixers are connected to the K receiving ends of the chip; the fourth beam splitter is used to split the local oscillator signal into K sub-local oscillator signals, and output the K sub-local oscillator signals to K mixers, and the K mixers are used to mix the K sub-local oscillator signals and the K echo signals received by the K receiving ends of the chip to obtain K intermediate frequency signals.

[0035] Based on the above example, the receiving range of the echo signal can be improved through K receiving paths. Even if the echo signal deviates from a certain distance, the probability of receiving the echo signal can be increased, thereby improving the receiving efficiency.

[0036] In a further possible example, the receiving component also includes a detection element, which is connected between the output ends of the K mixers and the electrical output end of the chip, and is used to perform photoelectric detection on the K intermediate frequency signals to obtain and output electrical signals.

[0037] Based on the above examples, the conversion of optical signals to electrical signals can be realized, and then the signal transmission from silicon optical signals to electrical chips can be realized.

[0038] In a second aspect, the present application provides a silicon photonic chip, comprising the waveguide structure in the above-mentioned first aspect, any design or example.

[0039] In one possible design, a silicon photonic chip includes a silicon substrate layer, a buried oxide layer, a waveguide layer, and a top oxide layer stacked in sequence, and the waveguide structure is located in the waveguide layer.

[0040] Based on the above design, silicon photonic chips can have the advantages of small size, doping capability, support for active device integration, high yield and low cost.

[0041] In a third aspect, the present application provides a detection device, comprising the waveguide structure in the above-mentioned first aspect or any design or example of the first aspect, or comprising the silicon photonic chip in the above-mentioned second aspect or any design of the second aspect.

[0042] In a possible design, the detection device further includes a light source assembly, which is used to emit an optical signal to the silicon photonic chip, and the optical signal is coupled into the waveguide structure through an end face coupler.

[0043] In one possible design, the detection device also includes a scanning component, which is used to scan the optical signal emitted by the silicon photonic chip into the detection space.

[0044] In one possible design, the detection device also includes a processing component, which is disposed on the electrical chip, and is used to determine the distance and / or speed of the target based on the electrical signal output by the silicon photonic chip.

[0045] In a fourth aspect, the present application provides a terminal device, comprising the waveguide structure in the above-mentioned first aspect or any design or example of the first aspect, or comprising the silicon photonic chip in the above-mentioned second aspect or any design of the second aspect, or comprising the detection device in the above-mentioned third aspect or any design of the third aspect.

[0046] The technical effects that can be achieved by the second to fourth aspects mentioned above can refer to the description of the beneficial effects in the first aspect mentioned above, and will not be repeated here one by one. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A schematic diagram showing a possible application scenario to which the present application is applicable;

[0048] Figure 2a The following is a schematic diagram showing the architecture of a currently mainstream FMCW LiDAR;

[0049] Figure 2b The schematic diagram of optical power transmission of silicon photonic chips in the current mainstream FMCW LiDAR is shown as an example;

[0050] Figure 3 The following is a schematic diagram of a structure provided by the industry to solve the TPA effect of silicon photonic chips;

[0051] Figure 4 A schematic structural diagram of a waveguide structure provided by the present application is exemplarily shown;

[0052] Figure 5a A possible structural schematic diagram of an end face coupler provided by the present application is exemplified;

[0053] Figure 5b An optical power transmission schematic diagram of an end coupler provided by the present application is exemplarily shown;

[0054] Figure 6 A schematic structural diagram of a waveguide structure provided by Embodiment 1 is exemplarily shown;

[0055] Figure 7a A schematic diagram of a structure for separating a local oscillator signal from an input signal of an end face coupler provided in Embodiment 1 is exemplarily shown;

[0056] Figure 7b A schematic diagram of a structure for separating a local oscillator signal from an input signal of a beam splitter provided in Embodiment 1 is exemplarily shown;

[0057] Figure 7c A schematic diagram of a structure for separating a local oscillator signal from a signal transmitted by a waveguide provided by the first embodiment is exemplarily shown;

[0058] Figure 7d Another structural schematic diagram of separating a local oscillator signal from a signal transmitted by a waveguide provided in Embodiment 1 is exemplarily shown;

[0059] Figure 8 A schematic structural diagram of a receiving component provided by the first embodiment is exemplarily shown;

[0060] Fig. 9 A schematic structural diagram of a waveguide structure provided by Embodiment 2 is exemplarily shown;

[0061] Fig.10a A schematic diagram of a structure for separating a local oscillator signal from a signal transmitted by a beam combiner and splitter provided in Embodiment 2 is exemplarily shown;

[0062] Fig.10b A schematic diagram of a structure for separating a local oscillator signal from an input signal of an end coupler provided by the second embodiment is exemplarily shown;

[0063] Fig.10c A schematic diagram of a structure for separating a local oscillator signal from a signal transmitted by a waveguide provided by the second embodiment is exemplarily shown;

[0064] Fig.10d Another structural schematic diagram of separating a local oscillator signal from a signal transmitted by a waveguide provided by Embodiment 2 is exemplarily shown;

[0065] Fig.11a A schematic diagram of the structure of a receiving component provided by the second embodiment is exemplarily shown;

[0066] Fig.11b A schematic diagram showing the structure of another receiving component provided by the second embodiment is exemplified;

[0067] Fig.12 A schematic structural diagram of a waveguide structure provided by Embodiment 3 is exemplarily shown;

[0068] Fig.13a A schematic structural diagram showing a waveguide structure including a receiving component provided in Embodiment 3 is exemplarily shown;

[0069] Fig.13b A schematic structural diagram showing, by way of example, a waveguide structure provided in Embodiment 3 including N receiving components;

[0070] Fig.13c A schematic structural diagram showing another waveguide structure including N receiving components provided in Embodiment 3 is exemplarily shown;

[0071] Fig.14 A possible structural schematic diagram of a silicon photonic chip provided by the present application is exemplified;

[0072] Fig.15 A possible structural schematic diagram of a detection device provided by the present application is exemplified;

[0073] Fig.16 A schematic diagram of the structure of a terminal device provided in the present application is exemplified. DETAILED DESCRIPTION

[0074] The embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0075] Below, some terms in this application are explained. It should be noted that these explanations are for the convenience of understanding by those skilled in the art and do not constitute a limitation on the scope of protection claimed in this application.

[0076] 1. Silicon-on-insulator (SOI)

[0077] SOI is a technology for growing semiconductor thin films on insulating substrates. It introduces a buried oxide layer between the top silicon and the back substrate, which can effectively isolate the current leakage and mutual interference between different parts inside the chip, and improve the performance and reliability of the device. Chips made based on SOI technology have the advantages of high speed, low power consumption, high reliability, and high temperature and high pressure resistance.

[0078] 2. Two-photo absorption (SPA) effect

[0079] The SPA effect refers to a molecule absorbing two photons at the same time, and the molecule transitions from the ground state to the excited state, passing through a virtual energy level in the middle, and the absorption intensity of the molecule is proportional to the square of the light intensity. The SPA effect only occurs under the action of strong light and is a kind of third-order nonlinear effect. For example, in lidar, the occurrence of the SPA effect is mainly concentrated at the focus of the ultra-strong laser generated by the laser, while the laser intensity elsewhere on the optical path is not enough to produce two-photon absorption. Simply put, if the ultra-strong laser generated by the laser is focused on the same single-mode waveguide of the SOI silicon photonic chip, then the single-mode waveguide will have a very strong SPA effect, the optical signal in the single-mode waveguide will be absorbed in large quantities, the output optical signal will become less, and the transmission loss will be large.

[0080] 3. Single-mode waveguide

[0081] A single-mode waveguide is a waveguide in which only one propagation mode of light can be propagated. This propagation mode is called the fundamental mode. Therefore, it can also be considered that only the fundamental mode of light waves is transmitted in a single-mode waveguide, while all higher-order modes of light waves are cut off. Different types of waveguides can have different single-mode conditions. The realization of single-mode conditions can avoid multi-mode interference and signal distortion, making waveguide transmission more stable and reliable.

[0082] 4. Edge coupler (EC)

[0083] EC is a coupler located at the edge of the optical chip, which is used to achieve the coupling connection between the single-mode waveguide and the optical device (such as laser, modulator or high-speed detector, etc.). Furthermore, it can achieve the coupling connection between the single-mode waveguide and the single-mode optical fiber. Usually, the mode field diameter (MFD) of the single-mode waveguide does not completely match the MFD of the single-mode optical fiber. For example, for silicon photonic chips, the MFD of its single-mode waveguide is 0.4-0.5μm, while the MFD of the single-mode optical fiber is 9-10μm. The difference between the two is large. If directly coupled, the coupling loss is about -20dB. Setting EC to achieve the coupling connection between the two allows the mode spots of the two to match, achieving a higher coupling efficiency.

[0084] 5. Mold spots

[0085] Mode spot, also known as mode field, refers to the electric field distribution that can be supported on the waveguide cross section. The parameter that measures the electric field distribution is the mode spot size. The mode spot size is related to the width of the waveguide cross section, the refractive index distribution and the operating wavelength.

[0086] 6. Linear Polarization

[0087] Linear polarization is a form of light propagation. Light with linear polarization is called linear polarization, also known as linear polarization or plane polarization. In the propagation direction of light, the electric vector of each point is in a certain plane. Since the trajectory of the electric vector endpoint is a straight line, it is called linear polarization. The vibration plane of linear polarization is fixed and will not deflect. Among them, the vibration plane refers to the plane formed by the direction of the light vector and the propagation direction of light.

[0088] Common linear polarized light includes P light, S light, TE light, and TM light. P light and S light are lights with different polarization directions expressed in space. Simply put, the light vector is decomposed into two mutually perpendicular vibration directions in space. The light with the vibration direction within the incident plane is called the parallel component of the light vector, referred to as P light, and the light with the vibration direction perpendicular to the incident plane is called the perpendicular component of the light vector, referred to as S light. TE light and TM light are lights with different polarization directions expressed from the perspective of chip integration, and are mostly used to describe the propagation characteristics of electromagnetic waves. TE light is also called transverse electric wave, and the electric field component is perpendicular to the propagation direction of the electromagnetic wave, that is, the electric field component is parallel to the incident plane. TM light is also called transverse magnetic wave, and the magnetic field component is perpendicular to the propagation direction of the electromagnetic wave, that is, the electric field direction is perpendicular to the incident plane.

[0089] 7. Signal to interference plus noise ratio (SINR)

[0090] SINR refers to the ratio of the strength of the received useful signal to the strength of the received interference signal, which can be simply understood as "signal-to-noise ratio". Among them, the interference signal includes noise and interference.

[0091] 8. Mixing

[0092] Mixing, also known as coherent demodulation, refers to the difference in frequency and phase between two signals. In FMCW LiDAR, the detection signal is usually a linear frequency modulation signal. After the linear frequency modulation signal interacts with the target object, the reflected echo signal (i.e., the received signal) will also have the same frequency change characteristics, but depending on the distance of the target, the echo signal will have a certain phase difference and frequency difference relative to the detection signal. Therefore, after receiving the echo signal, the echo signal and the detection signal can be mixed, that is, the frequency and phase of the detection signal and the echo signal are subtracted to obtain a low-frequency beat signal, which is also called a beat frequency signal or an intermediate frequency signal. The intermediate frequency signal contains the frequency difference information between the two signals, and the frequency difference is proportional to the target distance. At the same time, it also contains the Doppler effect information caused by the movement of the target, and the speed of the target can be calculated based on the Doppler effect information.

[0093] The foregoing text introduces some of the terms involved in this application. The following text introduces possible application scenarios of this application.

[0094] In a possible implementation, the waveguide structure provided in the present application can be applied to a detection device, and the detection device is installed in a transportation vehicle, such as but not limited to: a vehicle, a ship, an airplane, a drone, a train, a subway, an automated guided vehicle (AGV) or an unmanned transport vehicle, etc. For example, see Figure 1 , showing a possible application scenario of the present application, in which the detection device is installed at the front bumper of the vehicle as an example, the detection device can be used as an information collection source for path planning to assist the driver in achieving or automatically achieving safe driving of the vehicle. It is understandable that the detection device can also be installed at other locations of the vehicle, such as around the headlights, around the rearview mirrors, near the doors, at the rear bumper, behind the windshield or on the roof, etc., to capture the vehicle's surrounding environment information. When the detection device is installed behind the windshield, it has a lower requirement for no gravel collision risk, and will not affect the appearance of the vehicle. In addition, the front windshield itself has window heating and demisting and wiper cleaning functions.

[0095] It should be understood that the above application scenarios are only examples, and the detection device provided in the present application can also be applied to other possible scenarios, not limited to the scenarios exemplified above. For example, the detection device can also be installed on a road side unit (RSU) as a roadside traffic detection device to realize intelligent vehicle-road cooperative communication. For example, the detection device can also be installed in the cabin of a vehicle as a liveness detection device to detect and prompt the user of children or pets left in the cabin. For another example, the detection device can also be applied to a terminal device or a component provided in a terminal device. The terminal device can be, for example, a smart phone, a smart home device, a smart manufacturing device, a medical device, an industrial equipment, and a robot. They are not listed one by one here. It should be noted that the application scenarios described in this application are to more clearly illustrate the technical solution of the present application, and do not constitute a limitation on the technical solution provided in this application.

[0096] In addition, the above application scenarios can be applied to unmanned driving, assisted driving, intelligent driving, autonomous driving, connected vehicles, optical communications, security monitoring, biomedicine, surveying and mapping (such as three-dimensional mapping, remote sensing mapping), meteorological research, biomass and vegetation research, air quality monitoring, and aviation and aerospace applications.

[0097] The above detection device may include, for example, but is not limited to, a laser radar (light detection and ranging, LiDAR), such as a frequency modulated continuous wave laser radar (frequency modulated continuous wave LiDAR, FMCWLiDAR). Before introducing the specific solution provided by this application, the relevant content of FMCW LiDAR is introduced below.

[0098] See also Figure 2a , shows a schematic diagram of the architecture of a currently mainstream FMCW LiDAR, which includes a laser, an SOI silicon photonic chip and a scanning component, and the laser and the scanning component are arranged outside the SOI silicon photonic chip. The SOI silicon photonic chip is provided with an end coupler EC, a beam splitter 1, a beam splitter 21 and a beam splitter 22, and single-mode waveguides connected between these components, such as a single-mode waveguide B connected between EC and beam splitter 1. 1 , single-mode waveguide B connected between optical splitter 1 and optical splitter 21 21 , the single-mode waveguide B connected between the optical splitter 1 and the optical splitter 22 22 , and the single-mode waveguide B connected between the optical splitters 21 and 22 and the four transmitting ends of the SOI silicon photonic chip 31 , B 32 , B 33 and B 34 It should be noted that the figure only takes the SOI silicon photonic chip with 4 transmitting ends as an example for introduction, but the actual number of transmitting ends can be any integer greater than or equal to 2, and this application does not make a specific limitation.

[0099] by Figure 2a Taking the structure shown in the figure as an example, the EC is set at the left edge of the SOI silicon photonic chip (also called the left end face), and the laser sends a laser signal S to the left edge of the SOI silicon photonic chip. 1 , the laser signal S 1 is coupled to the single-mode waveguide B through EC 1 and passes through the single-mode waveguide B 1 The light is transmitted to the optical splitter 1, and then split into two sub-light signals by the optical splitter 1. The two sub-light signals pass through the single-mode waveguide B 21 and B 22 The optical signal is transmitted to the optical splitter 21 and the optical splitter 22, and is further split by the optical splitter 21 and the optical splitter 22 to form four sub-optical signals. The four sub-optical signals pass through four single-mode waveguides B 31 ~B 34 It is transmitted to the four transmitting ends of the SOI silicon photonic chip and emitted to the outside of the SOI silicon photonic chip, and then irradiated to the target through the scanning component, and reflected by the target to form an echo signal, which is used to measure the distance and / or speed of the target.

[0100] like Figure 2a As shown, after the optical signal is input to the left end face of the SOI silicon photonic chip, it is received by the EC set at the left end face. The optical signal output by the EC is related to the coupling loss of the EC, which is determined by the coupling efficiency of the EC at the end face and its own loss (also called transmission loss). When the coupling efficiency is not 100%, the optical power of the optical signal received by the EC is less than the optical signal input to the end face of the SOI silicon photonic chip. In the presence of the EC's own loss, the optical power of the optical signal output by the EC is less than the optical power of the optical signal received by the EC. Usually, the EC's own loss is relatively small and can be ignored. Therefore, it can also be considered that the optical power of the optical signal output by the EC is equal to or approximately equal to the optical power of the optical signal received by the EC.

[0101] exist Figure 2a In the scheme, the optical signals output by EC are coupled to the single-mode waveguide B 1 Without considering the loss of EC itself, all the optical power received by EC will enter the single-mode waveguide B. 1 In SOI silicon photonic chips, the cross-sectional area of ​​EC is smaller than that of single-mode waveguide B 1 The cross-sectional area of ​​the device is larger. When the optical power is constant, the optical power density in the device is inversely proportional to the cross-sectional area of ​​the device. Therefore, the optical power density in the EC is higher than that in the single-mode waveguide B. 1 The optical power density in the single-mode waveguide B 1 It is the part of the SOI silicon photonic chip that bears the highest optical power density and is most likely to produce the TPA effect, such as Figure 2b As shown. Through this single-mode waveguide B 1 The optical signal is then split into two single-mode waveguides B 21 , B 22 On each single-mode waveguide B 21 , B 22 The optical power on the single-mode waveguide B 1 The optical power in the single-mode waveguide B is low. 21 , B 22 The optical power density on the single-mode waveguide is less than that on the single-mode waveguide B 1 The optical power density on the single-mode waveguide B is similar. 31 ~B 34 The optical power density on the single-mode waveguide is less than that on the single-mode waveguide B 21 , B 22 The optical power density on the first single-mode waveguide B is not enough to produce the TPA effect. Therefore, the bottleneck of the TPA effect is in the first single-mode waveguide B. 1 superior.

[0102] As described in the background technology, the TPA effect of silicon optical waveguide will cause problems such as increased transmission loss, increased temperature and decreased reliability. 1 The industry has proposed a solution to the above problems caused by the TPA effect. Figure 3 As shown. This scheme places the first single-mode waveguide B 1 It is designed as a silicon ridge waveguide, and P doping and N doping are added on both sides to form a PN junction. At the same time, a reverse bias voltage is applied to the PN junction, so that the first waveguide B 1 When a high-power optical signal is passed, the carriers generated by the TPA effect are extracted from the first waveguide B by the PN junction. 1 , so that the first waveguide B 1 Maintain a low carrier concentration state to inhibit further absorption and heating of the optical signal by the carriers. In some scenarios, the extracted current can also be measured to form an ammeter to adjust the reverse bias voltage applied to the PN junction according to the real-time current signal to ensure that the first waveguide B 1 Maintain a state of low carrier concentration.

[0103] Although the above solutions can remove the carriers generated by the TPA effect by applying power, they cannot prevent the occurrence of the TPA effect. Moreover, some other problems will be introduced, mainly including the following two points: First, whether the first waveguide B 1 Whether it is designed as a ridge waveguide or doped with P ions and N ions on both sides, the process is relatively complex and the cost is high; secondly, adding power to the PN junction requires additional power consumption, and it will also generate current heating, which has reliability issues. Due to the existence of these problems, the above solutions provided by the industry are not very usable in FMCW LiDAR.

[0104] In view of this, the present application provides a waveguide structure, which uses a large-mode EC to directly split the input optical signal into two waveguides to reduce the optical power density in each waveguide and reduce the probability of the TPA effect. Compared with the solutions provided by the industry, the waveguide structure completely adopts a passive waveguide structure, does not require additional semiconductor process steps, and does not require any additional processes and additional power consumption such as doping and power-on. Therefore, it can solve the problems existing in the solutions provided by the above industry, and has the advantages of simple process, low cost, low power consumption, and high reliability.

[0105] The following is combined with Figure 4 To Attachment Fig.16 , the waveguide structure and related schemes proposed in this application are introduced in detail.

[0106] See also Figure 4, showing a schematic diagram of a waveguide structure provided by the present application. The waveguide structure 400 includes an EC 4111, a first waveguide 4112 and a second waveguide 4113. The EC 4111 has an input end a 11 , the first output terminal a 12 and the second output terminal a 13 The first waveguide 4112 is connected to the first output terminal a of the EC 4111. 12 The second waveguide 4113 is connected to the second output terminal a of the EC 4111. 13 The input terminal of EC 4111 is 11 Input the first optical signal S 11 , the first output terminal a of EC 4111 12 Output the second optical signal S 12 , the third output terminal a of EC 4111 13 Output the third optical signal S 13 . Further, wherein the first optical signal S 11 The optical power of the second optical signal S 12 The optical power and the third optical signal S 13 In one possible implementation, the input terminal a of EC 4111 11 The first waveguide 4112 and the second waveguide 4113 both have a second mode spot size, and the first mode spot size is larger than the second mode spot size.

[0107] In an ideal situation (ignoring the optical transmission loss), the first optical signal S 11 The optical power of the second optical signal S 12 The optical power and the third optical signal S 13 The sum of the optical powers of the second optical signal S 12 The optical power and the third optical signal S 13 The optical powers of the two optical signals can be the same or different. For example, in order to effectively reduce the optical power density in each waveguide, the difference in the optical power of the two optical signals can be configured to be less than a set value. In other words, the optical powers of the two optical signals are the same or close to each other. Taking the same as an example, EC 4111 can couple the first optical signal S 11 The power is equally divided into the second optical signal S 12 and the third optical signal S 13 Therefore, all the optical power coupled into EC 4111 is evenly divided into two waveguides 4121 and 4122, and the optical power density in each waveguide is only half of that in the existing solution, and the situation where all the optical power is in one waveguide will not occur.

[0108] It can be understood that in the ideal case of power sharing, the optical power in each waveguide is half of the input optical power. Therefore, when the same optical power density is contained in a single waveguide, the density of the first optical signal coupled to the EC 4111 can reach twice that of the prior art (+3dB). Based on this, if the waveguide structure is applied to the SOI silicon photonic chip, the probability of the TPA effect occurring in the waveguide of the SOI silicon photonic chip can be effectively reduced, thereby effectively reducing the optical transmission loss caused by the TPA effect in the waveguide. For example, after simulation testing, when other parameters remain unchanged, for target detection at the same distance, its detection SNR can be improved by about 3dB, and for the same detection SNR, its target ranging capability can be improved by about 41%, and the detection performance is effectively improved.

[0109] Optionally, the first waveguide 4112 and the second waveguide 4113 can be any type of waveguide, such as a single-mode waveguide, or a multi-mode waveguide. In one example, a single-mode waveguide can be selected as the first waveguide 4112 and the second waveguide 4113. The cross-sectional dimensions of a single-mode waveguide are smaller than those of a multi-mode waveguide, and the volume occupied is smaller, which can reduce the size of the chip where the waveguide structure is located. At the same time, it can also be adapted to scenarios where a single-mode optical signal needs to be transmitted, such as the transmitting component in an FMCW lidar. In addition, only a single mode is transmitted in a single-mode waveguide, and there will be no collision interference between multiple modes and multiple modes, so the transmission effect of the optical signal can also be improved.

[0110] It can be understood that the two output terminals of EC 4111 are 12 、a 13 They also have the second mode spot size. EC 4111 can be understood as a component composed of multiple waveguide units, which supports the input of a large mode spot. Under the action of multiple waveguide units, the large mode spot is coupled to the center of the mode spot at the two output ends, and gradually becomes two small mode spots. If the mode spot size of the two small mode spots is smaller than the second mode spot size, it is necessary to use a transition part to enlarge the mode spot size of the two small mode spots. When the mode spot sizes of the two small mode spots are enlarged to be equal to the second mode spot size, the position is used as the two output ends of EC 4111 and connected to the two waveguides 4121 and 4122. In this way, EC 4111 can convert a large mode spot input into two small mode spot outputs. Therefore, EC 4111 can also be called a large mode spot coupler.

[0111] As an example, see Figure 5a , showing a possible structural schematic diagram of EC 4111. Figure 5a (A) shows the three-dimensional structure of EC4111. Figure 5a (B) shows the top view of the EC4111. Figure 5aIn (A) and (B), the EC 4111 includes two waveguide units, namely waveguide unit 1 and waveguide unit 2, both of which are along the light propagation direction ( Figure 5a The shape gradually changes from narrow to wide from left to right, and the middle gradual part serves as a transition part. The mode spot size of the last wide part is the second mode spot size. If the two connected waveguides 4121 and 4122 are both single-mode waveguides, then it is equal to the mode spot size of the single-mode waveguide.

[0112] Figure 5b Show Figure 5a The optical power density diagram of the propagating optical signal in EC 4111, combined with Figure 5a and Figure 5b , the first optical signal S 11 It is input from the left end of waveguide unit 1 and waveguide unit 2, absorbed into the wide part of waveguide unit 1 and waveguide unit 2, coupled into the center of two small mode spots, and then the mode spot size is increased through the transition part. When it transitions to the second mode spot size, it is connected with the two waveguides 4121 and 4122.

[0113] It should be noted that the above content only gives a possible structure of EC 4111, and the EC 4111 may also have other structures. Any coupler that can input a large mode spot and output two small mode spots can be used as EC 4111 in this application, and this application does not make specific restrictions on this.

[0114] Based on the above structure, a large mode spot EC can be used to directly split the input optical signal into two waveguides, reduce the optical power in a single waveguide, and make it less likely for a high optical power density to appear in a single waveguide. When the waveguide is a waveguide in an SOI silicon photonic chip (abbreviated as SOI waveguide), the SOI waveguide is not prone to TPA effect, which can solve the problem caused by the TPA effect of the SOI waveguide under high optical power density. In other words, when the optical power density in the SOI waveguide is the same as that in the prior art, the SOI silicon photonic chip can support higher optical power input than the prior art, and can increase the maximum optical power that the SOI silicon photonic chip can withstand. In addition, the above structure completely adopts a passive waveguide structure, which can be directly formed through one exposure without adding additional semiconductor process steps, nor does it require any additional processes such as doping and power-up and additional power consumption. It has the advantages of simple process, extremely simple architecture, extremely low cost, extremely high performance, and extremely high reliability.

[0115] Optionally, in Figure 4In the waveguide structure shown, EC 4111, first waveguide 4112 and second waveguide 4113 are located in the transmitting assembly. The waveguide structure 400 may include one transmitting assembly or multiple transmitting assemblies. The following describes in detail the scheme including one or more transmitting assemblies through implementation schemes 1 to 3 respectively.

[0116] Embodiment 1: includes a launch assembly.

[0117] See also Figure 6 , showing a schematic diagram of the structure of a waveguide structure provided by Implementation Example 1. In this example, in addition to the above EC 4111, the first waveguide 4112 and the second waveguide 4113, the transmitting component also includes a first beam splitter 4114 and a second beam splitter 4115. The waveguide structure 400 is located on a chip, such as an SOI silicon photonic chip. The chip includes at least two first transmitting ends and at least two second transmitting ends. The number of the at least two first transmitting ends and the number of the at least two second transmitting ends may be the same or different, and there is no limitation. The first beam splitter 4114 is connected to the output end of the first waveguide 4112 and the at least two first transmitting ends of the chip where the waveguide structure 400 is located (the two first transmitting ends b are shown in the figure). 1 、b 2 As an example), the second beam splitter 4115 is connected to the output end of the second waveguide 4113 and at least two second emitting ends of the chip (the two second emitting ends b are shown in the figure). 3 、b 4 For example, the connection method may be a waveguide connection, an optical fiber connection, or any other connection that can realize optical signal transmission, without limitation.

[0118] Based on the above structure and connection relationship, the first beam splitter 4114 can split at least two first emission signals from the input optical signal, and output at least two first emission signals through its at least two output ends, and at least two first emission signals are emitted to the scanning component through at least two first emission ends of the chip, and are scanned to the detection space by the scanning component. Similarly, the second beam splitter 4115 can split at least two second emission signals from the input optical signal, and output at least two second emission signals through its at least two output ends, and at least two second emission signals are also emitted to the scanning component through at least two second emission ends of the chip, and are scanned to the detection space by the scanning component.

[0119] It should be noted that the number of at least two first transmission signals and the number of at least two second transmission signals may be the same or different. The figure takes the number 2 as an example, but it may also be 2 first transmission signals and 3 second transmission signals, or 4 first transmission signals and 2 second transmission signals, or 3 first transmission signals and 3 second transmission signals, and so on, without limitation.

[0120] Optionally, at least two first transmission signals and at least two second transmission signals are used to measure the target. Figure 6 For example, the two first transmission signals and the two second transmission signals in the example, these four transmission signals can correspond to four detection channels, and the four transmission signals are scanned to four areas by the subsequent scanning components. In this way, four areas can be detected through one scan, the scanning range of one detection becomes larger, and the detection efficiency is improved. Among them, each area can be a point, a line or a surface, etc., without limitation.

[0121] Optionally, the optical power of at least two first transmission signals and at least two second fourth transmission signals is the same. For example, in one example, the first beam splitter 4114 and the second beam splitter 4115 are both power beam splitters, and the EC 4111 generates a power beam splitter according to the input first optical signal S 11 Equal power sharing (for example, for the first optical signal S 11 The remaining optical signal after the local oscillator (LO) signal is separated is equally divided to obtain the second optical signal S 12 and the third optical signal S 13 , the second optical signal S 12 The optical signal S is input to the first beam splitter 4114 and is equally divided into at least two first transmission signals and a third optical signal S by the first beam splitter 4114. 13 The optical power is input to the second beam splitter 4115, and the second beam splitter 4115 equally splits the optical power into at least two second transmission signals. Based on this method, at least four transmission signals will have the same optical power, and at least four transmission signals can hit the same distance in the detection space, thereby obtaining detection results of different areas at the same distance. This detection method has the best detection effect.

[0122] It should be noted that using the first beam splitter and the second beam splitter to split at least four transmission signals to merge and detect the target is only one possible implementation. In another implementation, the second optical signal S output by EC 4111 can also be directly 12 and the third optical signal S 13As two transmission signals to directly detect the target, in this case, the chip where the waveguide structure 400 is located may have only two transmission ends, and the output ends of the first waveguide 4112 and the second waveguide 4113 are directly connected to the two transmission ends. Alternatively, in another implementation, one of the optical signals output by EC 4111 can be used as a transmission signal, and the other optical signal can be split into two transmission signals through a beam splitter, and these three transmission signals can be used to detect the target. Alternatively, in another implementation, more beam splitters can be used to split any number of more than four transmission signals to further increase the detection range. And so on, there are many possible implementations, which are not listed here one by one.

[0123] Alternatively, if Figure 6 As shown, the waveguide structure 400 may also include a receiving component 421, which is used to obtain the local oscillation signal S 14 and the echo signal S 15 , and the local oscillator signal S 14 and the echo signal S 15 Mixing is performed to obtain an intermediate frequency signal, which is used to determine the speed and / or distance of the target. The receiving component 421 can receive the target from the receiving end c 1 The received echo signal S 15 For example, an input end of the receiving component 421 can be connected to the receiving end c of the chip through a waveguide, an optical fiber or other means that can transmit optical signals. 1 The above transmission signal is reflected by the target and becomes the echo signal S 15 , and returns to the receiving end of the chip c 1 , so that the receiving component 421 can receive 1 The echo signal S is received 15 .

[0124] In addition, the local oscillator signal S 14 The signal can be separated from the input signal, the transmitted signal or the output signal of any device among EC 4111, first waveguide 4112, second waveguide 4113, first beam splitter 4114, second beam splitter 4115, the waveguide after first beam splitter 4114 or the waveguide after second beam splitter 4115. For ease of understanding, three possible examples are given below.

[0125] For example 1, see Figure 7a , showing a possible structure diagram of separating the local oscillator signal from the input signal of EC 4111. In this structure, EC 4111 also has a third output terminal a 14 The other input terminal of the receiving component 421 is connected to the third output terminal a of EC4111. 14 EC 4111 receives the first optical signal S11 After that, the first optical signal S 11 Coupled to three output terminals a 12 ~a 14 On, the first output terminal a 12 Output the second optical signal S 12 , the second output terminal a 13 Output the third optical signal S 13 , the third output terminal a 14 Output local oscillator signal S 14 , the receiving component 421 receives the signal from the third output terminal a 14 Receive the local oscillator signal S 14 .

[0126] Optionally, the local oscillator signal S 14 The optical power of the second optical signal S 12 The optical power and the third optical signal S 13 For example, EC 4111 converts the first optical signal S 11 The relatively small power optical signal is coupled to the third output terminal a 14 The remaining high-power optical signal is coupled to the first output terminal a by power sharing. 12 and the second output terminal a 13 Furthermore, the first beam splitter 4114 and the second beam splitter 4115 also perform power equalization processing, so that at least four transmission signals emitted by at least four transmitting ends of the chip will have equal power, and at least four detection channels will emit light evenly.

[0127] Optionally, the receiving component 421 can be connected to the third output terminal a through a waveguide, an optical fiber or other means capable of transmitting an optical signal. 14 For example, Figure 7a The figure shows the connection through a waveguide. In this case, the third output end of EC 4111 can also have a second mode spot size. In other words, the three output ends of EC 4111 a 12 ~a 14 Both can be connected to a waveguide, such as a single-mode waveguide.

[0128] For example 2, see Figure 7b , showing a possible structure diagram of the local oscillator signal being separated from the input signal of the second beam splitter 4115. In this structure, assuming that the second beam splitter 4115 separates two second transmission signals, the second beam splitter 4115 also has a third output terminal, and the other input terminal of the receiving component 421 is connected to the third output terminal of the second beam splitter 4115. The second beam splitter 4115 receives the third optical signal S 13 After that, from the third optical signal S 13 The light is split into two second transmission signals and a local oscillator signal S14 , local oscillator signal S 14 The second transmission signals are output through the third output terminal and enter the receiving component 421, while the two second transmission signals are transmitted to the two second transmission terminals b 3 and b 4 , and emitted to the detection space.

[0129] Optionally, the local oscillator signal S 14 The optical power of the third optical signal S is less than the optical power of any second transmission signal. 13 The optical signal with relatively low power is separated from the first beam splitter 4111 and outputted from the third output terminal, while the remaining high power optical signal is outputted from the first two output terminals by means of power equalization. In this case, the optical power of the two second transmission signals can be guaranteed to be the same. If the EC 4111 and the first beam splitter 4114 also equally divide the optical signals, the optical power of the two first transmission signals will be different from the optical power of the two second transmission signals, specifically, it will be greater than the optical power of the two second transmission signals.

[0130] For example three, see Figure 7c and 7d , showing two possible structural diagrams for separating the local oscillator signal from the signal transmitted by the second waveguide 4113. In this structure, the waveguide structure 400 further includes a light splitting element 413, which is coupled or connected between the second waveguide 4113 and the other input end of the receiving component 421. The light splitting element 413 is used to separate the third optical signal S transmitted from the second waveguide 4113. 13 The split light is the local oscillator signal S 14 , and the local oscillator signal S 14 In this case, the optical power of the optical signal entering the second beam splitter 4115 is less than the optical power of the optical signal at the second output end a of the EC 4111. 22 The output third optical signal S 13 Optionally, the local oscillator signal S 14 The optical power of the optical signal S is less than the optical power of the optical signal entering the second beam splitter 4115. 13 A relatively small-power optical signal is separated and output to the receiving component 421 , while the remaining large-power optical signal is output to the second beam splitter 4115 .

[0131] The light splitting element 413 may be a directional coupler, such as Figure 7c The directional coupler does not contact the second waveguide 4113, but is relatively close to the second waveguide 4113. In other words, a directional coupler can be placed close enough to the second waveguide 4113 so that the directional coupler transmits the third optical signal S from the second waveguide 4113. 13The local oscillator signal S is split into different powers 14 Alternatively, the light splitting element 413 may also be a beam splitter, such as Figure 7d As shown, the beam splitter is directly inserted in the middle of the second waveguide 4113 to split the third optical signal S transmitted in the second waveguide 4113. 13 The light is split into the local oscillator signal S 41 and measure optical signals.

[0132] It can be understood that the above three examples are only given to separate the local oscillator signal S from the input signal. 14 There are several possible structures. Other separated structures can be obtained by analogy with the above structures, and they will not be repeated here one by one.

[0133] Optionally, the receiving component 421 may be any component or combination thereof that can implement a frequency mixing function. Figure 7c For example, see the structure shown in Figure 8 , showing a specific structural diagram of a receiving component provided by the first embodiment. Figure 7c and Figure 8 In this example, the receiving component 421 includes a fourth beam splitter 4211 and K mixers, where K is an integer greater than or equal to 2. Taking K as 4 as an example, Figure 8 As shown, the receiving component 421 may include a fourth beam splitter 4211 and four mixers, namely mixer 42121, mixer 42122, mixer 42123 and mixer 42124. The input end of the fourth beam splitter 4211 is the input end of the receiving component 421, and is used to obtain the local oscillator signal S 14 The four output ends of the fourth beam splitter 4211 are respectively connected to the four first input ends of the four mixers 42121 to 42124, and the four second input ends of the four mixers 42121 to 42124 are connected to the four receiving ends of the chip. 11 、c 12 、c 13 and c 14 Here, the connection between the various components can be achieved through waveguides, optical fibers or other methods that can transmit optical signals. Figure 8 Take waveguide connection as an example.

[0134] Based on this structure and connection relationship, the input end of the fourth beam splitter 4211 can receive the local oscillator signal S 14 The fourth beam splitter 4211 converts the local oscillator signal S 14 Split (e.g., equal power splitting) into four sub-LO signals S 141 , S 142 , S 143 , S 144 and transmits these four sub-local oscillator signals S through its four output terminals. 141~S 144 The four mixers 42121 to 42124 can also receive the four receiving terminals of the chip. 11 ~c 14 Receive four echo signals S 151 , S 152 , S 153 , S 154 Each mixer performs a mixing operation on the received sub-local oscillator signal and the echo signal to generate its own intermediate frequency signal. The four intermediate frequency signals generated by the four mixers 42121-42124 are used to combine and determine the distance and / or speed of the target, in other words, to jointly achieve target measurement.

[0135] Optionally, the four mixers 42121-42124 are combined with subsequent components to achieve the target measurement. Figure 7c and Figure 8 As shown, the receiving component 421 may also include a detection element 4213, which is connected between the output ends of the four mixers 42121~42124 and the electrical output end d of the chip, and is used to perform photoelectric detection on the four intermediate frequency signals generated by the four mixers 42121~42124, obtain an electrical signal and output it. The electrical signal is transmitted to subsequent components, such as an electrical chip, through the electrical output end d of the chip, and the intermediate frequency signal is processed in the electrical chip to obtain point cloud data and determine the distance and / or speed of the target. For related content, please refer to the introduction of the detection device below, which will not be described in detail here.

[0136] Optionally, one transmitting component is used to transmit an optical signal of one wavelength. In the first embodiment, since the waveguide structure 400 includes one transmitting component, the wavelengths of the four transmitting signals are the same, and the four sub-local oscillator signals S 141 ~S 144 The wavelengths of the four intermediate frequency signals are also the same. Each mixer can mix the signal with the same wavelength as the sub-local oscillator signal in the received echo signal, and discard the signals of other wavelengths. Therefore, the four intermediate frequency signals are all signals of the same wavelength, and the wavelength is the same as the wavelength of the transmitted signal. The measurement target is measured based on these four intermediate frequency signals, which can improve the measurement accuracy.

[0137] Based on the above implementation scheme one, a transmitting component and a receiving component can be set in the waveguide structure, and the local oscillator signal of the receiving component can be separated from the relevant signal of any component in the transmitting component. Therefore, the waveguide structure has high flexibility and versatility and can be adapted to various detection occasions.

[0138] Implementation scheme 2: includes two transmitting components.

[0139] See also Fig. 9, showing a schematic diagram of a waveguide structure provided by the second embodiment. In this example, the waveguide structure 400 includes two transmitting components, each of which includes the EC, the first waveguide and the second waveguide described above. Fig. 9 As shown, one of the transmitting components includes EC 4111, a first waveguide 4112 and a second waveguide 4113, and the other transmitting component includes EC 4121, a first waveguide 4122 and a second waveguide 4123. In this case, the waveguide structure 400 also includes a first beam combiner 431 and a second beam combiner 432. The chip where the waveguide structure 400 is located includes two first transmitting terminals b 1 、b 2 and two second transmitting terminals b 3 、b 4 For example, the first beam combiner 431 and the second beam splitter 432 each have two input ends and two output ends. The two input ends of the first beam combiner 431 are respectively connected to the output ends of the two first waveguides 4112 and 4122 in the two transmitting components, and the output end of the first beam combiner 431 is connected to the two first transmitting ends b of the chip. 1 、b 2 The two input ends of the second beam combiner / splitter 432 are respectively connected to the output ends of the two second waveguides 4113 and 4123 in the two transmitting components, and the output end of the second beam combiner / splitter 432 is connected to the two second transmitting ends b of the chip. 3 、b 4 .

[0140] Based on the structure and connection relationship, in the transmitting component above, EC 4111 receives the first optical signal S 11 The second optical signal S is split into 12 and the third optical signal S 13 , the second optical signal S 12 The third optical signal S is transmitted to the first beam combiner / splitter 431 through the first waveguide 4112. 13 The first optical signal S is transmitted to the second beam combiner 432 through the second waveguide 4113. 21 The second optical signal S is split into 22 and the third optical signal S 23 , the second optical signal S 22 The third optical signal S is transmitted to the first beam combiner / splitter 431 through the first waveguide 4122. 23 The first beam combiner / splitter 431 splits the two optical signals input into two first transmission signals, and outputs the two first transmission signals through its two output terminals, so that the two first transmission signals are transmitted to the two first transmission terminals b of the chip.1 、b 2 The second beam combiner 432 splits the two input optical signals into two second emission signals, and outputs the two second emission signals through its two output terminals, so that the two second emission signals are transmitted to the two second emission terminals b of the chip. 3 、b 4 , and also emitted to the scanning component.

[0141] Optionally, the two first transmission signals and the two second transmission signals are scanned to the detection space by the scanning component to measure the target in the detection space. For example, the two first transmission signals and the two second transmission signals correspond to four detection channels. More specifically, the two first transmission signals and the two second transmission signals are scanned to four areas by the subsequent scanning component. In this way, four areas can be detected through one scan, the scanning range of one detection becomes larger, and the detection efficiency is improved.

[0142] Optionally, the optical power of the two first transmission signals and the two second transmission signals is the same. For example, in one example, the first beam combiner 431 and the second beam combiner 432 are both power beam splitters, and EC 4111 and EC 4121 both obtain the second optical signal and the third optical signal by equal power division according to the input first optical signal (for example, equal power division of the remaining optical signal after the local oscillator signal is separated from the first optical signal), and the two second optical signals are input to the first beam combiner 431, and are equally divided into the two first transmission signals after being combined by the first beam combiner 431, and the two third optical signals are input to the second beam combiner 432, and are equally divided into the two second transmission signals after being combined by the second beam combiner 432. Based on this method, the four transmission signals will have the same optical power, and the four transmission signals can hit the same distance in the detection space, so as to obtain detection results of different areas at the same distance. The detection effect under this detection method is the best.

[0143] In one example, two first optical signals S in two transmitting components 11 , S 21 In other words, the first optical signal S 11 With a first wavelength, the first optical signal S 21 has a second wavelength, and the first wavelength is different from the second wavelength. Based on this, from the two first optical signals S 11 , S 21 The two second optical signals S 12 , S 22 Also with different wavelengths, the two third optical signals S 13 , S 23Therefore, the first beam combiner 431 and the second beam combiner 432 will receive two input signals with different wavelengths, and each beam combiner will combine the two received input signals with different wavelengths and divide them into two dual-wavelength transmission signals and output them. Therefore, each transmission signal is a dual-wavelength signal, and each transmission signal can detect more distances, which can improve the comprehensiveness of detection.

[0144] Or, in another example, the two first optical signals S in the two transmitting components 11 , S 21 have the same wavelength but different linear polarization states. In other words, the two first optical signals S 11 , S 21 are lights of different linear polarization states. For example, the first optical signal S 11 The first optical signal S is TE light. 21 is TM light, or the first optical signal S 11 The first optical signal S is TM light. 21 is TE light, or the first optical signal S 11 The first optical signal S is P light. 21 is S light, or the first optical signal S 11 The first optical signal S is S light. 21 In this case, a polarization element, such as a polarization beam splitter (PBS) or a polarization beam rotator (PSR), is also required in the waveguide structure 400. The polarization element splits the echo signals corresponding to different transmitting components based on different linear polarization states, so as to mix the echo signals corresponding to each transmitting component.

[0145] Or, in another example, the two first optical signals S in the two transmitting components 11 , S 21 It has the same wavelength and the same linear polarization state, but a polarization element is provided in the waveguide structure 400, and the polarization element is used to perform polarization splitting on the echo signal, thereby separating the echo signals corresponding to different transmitting components, and mixing the echo signals corresponding to each transmitting component.

[0146] It should be noted that, regarding the implementation method of polarization element splitting the echo signals corresponding to different transmitting components, reference can be made to the existing solutions, which will not be introduced in detail here.

[0147] Optionally, in Fig. 9In the example, four dual-wavelength emission signals are generated by a beam combiner and splitter to combine and detect the target. This is only one possible implementation. In another implementation, the two second optical signals S output by EC 4111 can also be directly 12 and the third optical signal S 13 , and two second optical signals S output by EC 4121 22 and the third optical signal S 23 As four transmission signals to directly detect the target, in this case, the chip still has four transmission ends, and the output ends of the first waveguides 4112 and 4122, and the second waveguides 4113 and 4123 are directly connected to the four transmission ends, but the four transmission signals emitted by the four transmission ends are all single-wavelength signals, two of which are one wavelength, and the other two are another wavelength. Alternatively, in another implementation, one of the optical signals output by EC 4111 and one of the optical signals output by EC 4121 can be directly used as two single-wavelength transmission signals, and another optical signal output by EC 4111 and another optical signal output by EC 4121 can be split into two dual-wavelength transmission signals through a beam combiner and splitter, and these four transmission signals can be used to detect the target. Alternatively, in another implementation, more beam splitters or beam combiners and splitters can be used to split any number of more than four transmission signals to further increase the detection range. And so on, there are many possible implementations, which are not listed here one by one.

[0148] Alternatively, if Fig. 9 As shown, the waveguide structure 400 may also include a receiving component, which is used to obtain a local oscillator signal and an echo signal, and mix the local oscillator signal and the echo signal to obtain an intermediate frequency signal, which is used to determine the speed and / or distance of the target. The receiving component can receive the echo signal from the receiving end c of the chip. For example, an input end of the receiving component can be connected to the receiving end c of the chip through a waveguide, an optical fiber or other means that can transmit optical signals. The above transmission signal is reflected by the target and becomes an echo signal, and returns to the receiving end c of the chip, so that the receiving component can receive the echo signal from the receiving end c.

[0149] In addition, there may be one or more receiving components, and the local oscillator signal of each receiving component may be separated from the input signal, the transmitted signal, or the output signal of any device among EC (i.e., EC4111 and EC 4121), the first waveguide (i.e., the first waveguide 4112 and the first waveguide 4122), the second waveguide (i.e., the second waveguide 4113 and the second waveguide 4123), the first beam combiner 431, the second beam combiner 432, the waveguide after the first beam combiner 431, or the waveguide after the second beam combiner 432. For ease of understanding, four possible examples are given below.

[0150] For example 1, see Fig.10a , showing a possible structure diagram of separating the local oscillator signal from the signal transmitted by the second beam combiner / splitter 432. In this structure, there is only one receiving component, called receiving component 421, and the second beam combiner / splitter 432 also has a third output terminal. One input terminal of the receiving component 421 is connected to the receiving terminal c of the chip, and the other input terminal is connected to the third output terminal of the second beam combiner / splitter 432. The second beam combiner / splitter 432 receives two third optical signals S 13 , S 23 After that, firstly convert the two third optical signals S 13 , S 23 Combined into one beam, and then split into two second transmission signals and local oscillator signal S 4 , local oscillator signal S 4 The second transmission signals are output through the third output terminal and enter the receiving component 421, while the two second transmission signals are transmitted to the two transmission terminals b. 3 and b 4 , and emitted to the detection space.

[0151] Optionally, between the two third optical signals S 13 , S 23 When the wavelengths of the two third optical signals S 13 , S 23 The local oscillator signal S is split from the dual-wavelength optical signal into a dual-wavelength optical signal. 4 The receiving component 421 can be based on the local oscillator signal S 4 The two wavelengths of the echo signal and the local oscillator signal S 4 The signals of the two wavelengths are mixed to directly obtain the intermediate frequency signals of the two wavelengths, while the signals of other wavelengths in the echo signal are directly filtered out as noise signals.

[0152] Optionally, the local oscillator signal S 4 The optical power of the third optical signal S is less than the optical power of any second transmission signal. 13 The optical signal with relatively low power is separated from the optical signal and outputted from the third output port, while the remaining high power optical signal is outputted from the first two output ports by power equalization. In this case, the optical power of the two second transmission signals can be guaranteed to be the same. If EC 4111, EC 4121 and the second beam combiner 432 also equally divide the optical signals with equal power, the optical power of the two first transmission signals will be different from the optical power of the two second transmission signals, specifically, it will be greater than the optical power of the two second transmission signals.

[0153] For example 2, see Fig.10b, showing a possible structural diagram of separating the local oscillator signal from the input signal of EC 4111 and EC 4121. In this structure, there are two receiving components, namely receiving component 421 and receiving component 422. Receiving component 421 corresponds to the transmitting component where EC 4111 is located, and receiving component 422 corresponds to the transmitting component where EC 4121 is located.

[0154] For the receiving component 421, the EC 4111 also has a third output terminal a 14 , an input terminal of the receiving component 421 is connected to the receiving terminal c of the chip 1 The other input terminal is connected to the third output terminal a of EC 4111 14 EC 4111 receives the first optical signal S 11 After that, the first optical signal S 11 Coupled to its three output terminals a 12 、a 13 、a 14 On, the first output terminal a 12 Output the second optical signal S 12 , the second output terminal a 13 Output the third optical signal S 13 , the third output terminal a 14 Output local oscillator signal S 14 Assume that the first optical signal S 11 With the first wavelength, the local oscillator signal S 14 Also having the first wavelength, the receiving component 421 receives the signal from the third output terminal a of the EC 4111. 14 Receive the local oscillator signal S of the first wavelength 14 and from the receiving end of the chip c 1 Receive the echo signal S 15 , using the echo signal S 15 The signal of the first wavelength and the local oscillator signal S 14 Mixing is performed to obtain an intermediate frequency signal of the first wavelength.

[0155] Similarly, for the receiving component 422, the EC 4121 also has a third output terminal a 24 , an input terminal of the receiving component 422 is connected to the receiving terminal c of the chip 2 The other input terminal is connected to the third output terminal a of EC 4121 24 EC 4121 receives the first optical signal S 21 After that, the first optical signal S 21 Coupled to its three output terminals a 22 、a 23 、a 24 On, the first output terminal a 22Output the second optical signal S 22 , the second output terminal a 23 Output the third optical signal S 23 , the third output terminal a 24 Output local oscillator signal S 24 Assume that the second optical signal S 21 With a second wavelength, the local oscillator signal S 24 Also having a second wavelength, the receiving component 422 receives the signal from the third output terminal a of the EC 4121. 24 The local oscillator signal S of the second wavelength is received 24 and from the receiving end of the chip c 2 Receive the echo signal S 25 , using the echo signal S 25 The second wavelength signal and the local oscillator signal S 24 Mixing is performed to obtain an intermediate frequency signal of a second wavelength.

[0156] It can be understood that the local oscillator signal is single-wavelength, but the four transmission signals are dual-wavelength. Therefore, each echo signal also has at least two wavelengths. When each echo signal performs a mixing operation in the corresponding receiving component, it is only mixed with a single wavelength of the current local oscillator signal, and signals of other wavelengths are discarded to improve the quality of the intermediate frequency signal.

[0157] Optionally, for each EC, the optical power of the local oscillator signal separated is less than the optical power of the second optical signal and the optical power of the third optical signal separated. 11 The relatively small power optical signal is coupled to the third output terminal a 14 The remaining high-power optical signal is coupled to the first output terminal a by power sharing. 12 and the second output terminal a 13 EC 4121 converts the first optical signal S 21 The same low-power optical signal is coupled to the third output terminal a 24 The remaining high-power optical signal is coupled to the first output terminal a by power sharing. 22 and the second output terminal a 23 Furthermore, the first beam combiner 431 and the second beam combiner 432 also perform power equalization processing, so that the four transmission signals emitted by the four transmitting ends of the chip will be of equal power, and the four detection channels will emit light evenly.

[0158] For example three, see Fig.10c, showing a possible structural diagram of separating the local oscillator signal from the signal transmitted by the first waveguide 4112 and the second waveguide 4123. In this structure, there are also two receiving components, namely, receiving component 421 and receiving component 422. Receiving component 421 corresponds to the transmitting component where EC 4111 is located, and receiving component 422 corresponds to the transmitting component where EC 4121 is located.

[0159] For the receiving component 421, the waveguide structure 400 further includes a directional coupler 431, which is coupled between the first waveguide 4112 and an input end of the receiving component 421, and the other input end of the receiving component 421 is connected to the receiving end c of the chip. 1 The directional coupler 431 does not contact the first waveguide 4112, but is relatively close to the first waveguide 4112. Therefore, it can transmit the second optical signal S from the first waveguide 4112. 12 The local oscillator signal S is coupled out 14 , and the local oscillator signal S 14 Output to the receiving component 421. Assuming that the first optical signal S 11 With the first wavelength, the second optical signal S 12 The receiving component 421 receives the second optical signal S via the directional coupler 431. 12 The local oscillator signal S of the first wavelength is coupled out 14 and from the receiving end of the chip c 1 Receive the echo signal S 15 , using the echo signal S 15 The signal of the first wavelength and the local oscillator signal S 14 Mixing is performed to obtain an intermediate frequency signal of the first wavelength.

[0160] Similarly, for the receiving component 422, the waveguide structure 400 further includes a directional coupler 432, which is coupled between the second waveguide 4123 and an input end of the receiving component 422, and the other input end of the receiving component 422 is connected to the receiving end c of the chip. 2 The directional coupler 432 does not contact the second waveguide 4123, but is relatively close to the second waveguide 4123. Therefore, the directional coupler 432 can transmit the third optical signal S from the second waveguide 4123. 23 The local oscillator signal S is coupled out 24 , and the local oscillator signal S 24 Output to the receiving component 422. Assuming that the first optical signal S 21 With the second wavelength, the third optical signal S 23 The receiving component 422 receives the third optical signal S via the directional coupler 432. 23 The local oscillator signal S of the second wavelength is coupled out 24and from the receiving end of the chip c 2 Receive the echo signal S 25 , using the echo signal S 25 The second wavelength signal and the local oscillator signal S 24 Mixing is performed to obtain an intermediate frequency signal of a second wavelength.

[0161] Based on the above splitting method, the optical power of the optical signal entering the beam combiner will be less than the optical power of the optical signal output by the EC to the split waveguide. For example, the optical power of the optical signal entering the first beam combiner 431 is less than the optical power of the second optical signal S output by the EC 4111 to the first waveguide 4112. 12 The optical power of the optical signal entering the second beam combiner 432 is less than the optical power of the third optical signal S outputted from the EC 4121 to the second waveguide 4123. 23 of optical power.

[0162] Optionally, on the split optical waveguide, the optical power of the split local oscillator signal is less than the optical power of the optical signal entering the subsequent beam combiner / splitter. 12 The directional coupler 432 extracts the relatively low-power optical signal from the third optical signal S and outputs it to the receiving component 421, while the remaining high-power optical signal is output to the first beam combiner 431. 23 The relatively low-power optical signal is separated from the beam and output to the receiving component 422, while the remaining high-power optical signal is output to the second beam combiner 432. In this way, the relatively high-power light beam can be used as the transmission signal as much as possible to improve the target detection effect.

[0163] It can be understood that the above directional coupler is a type of light splitting element, and the above directional coupler can also be replaced by other elements that can realize the light splitting function, such as a beam splitter. Taking the beam splitter as an example, the light splitting method can also have the following example 4:

[0164] For example 4, see Fig.10d , shows another possible structural diagram of the local oscillator signal being separated from the signal transmitted by the first waveguide 4112 and the second waveguide 4123. The difference between this structure and the structure in the above-mentioned Example 3 is that the directional coupler 431 in Example 3 is replaced by the beam splitter 433 in Example 4, and the directional coupler 432 in Example 3 is replaced by the beam splitter 434 in Example 4. The directional coupler couples the local oscillator signal from the waveguide in a non-contact but sufficiently close manner, while the beam splitter is directly inserted into the waveguide. It can be considered that the input end of the beam splitter is connected to the output end of the waveguide, and the two output ends of the beam splitter are connected to the subsequent components through the waveguide.

[0165] For example, Fig.10dThe input end of the beam splitter 433 is connected to the output end of the first waveguide 4112, and the two output ends are respectively connected to an input end of the first beam combiner 431 and an input end of the receiving component 421. The beam splitter 433 converts the second optical signal S output from the first waveguide 4112 into 12 Splitting is used to measure the optical signal and the local oscillator signal S 14 , outputs the measurement optical signal to the first beam combiner / splitter 431 to participate in the target measurement, and outputs the local oscillator signal S 14 Output to the receiving component 421 to complete the echo signal S 15 Similarly, the input end of the beam splitter 434 is connected to the output end of the second waveguide 4123, and the two output ends are respectively connected to an input end of the second beam combiner 432 and an input end of the receiving component 422. The beam splitter 434 converts the third optical signal S output from the second waveguide 4123 into 23 Splitting is used to measure the optical signal and the local oscillator signal S 24 , outputs the measurement optical signal to the second beam combiner / splitter 432 to participate in the target measurement, and outputs the local oscillator signal S 24 Output to the receiving component 422 to complete the echo signal S 25 of mixing.

[0166] It can be understood that the above four examples are only several possible structures for separating the local oscillator signal from the input signal. Other separation structures can be obtained by analogy with the above structures, and they will not be repeated here one by one.

[0167] Optionally, the above receiving components can be any components or combinations thereof that can realize the frequency mixing function. Fig.10a For example, see the structure shown in Fig.11a , showing a specific structural diagram of a receiving component provided by Implementation Example 2. Fig.10a and Fig.11a In this example, the receiving component 421 includes a fourth beam splitter 4211 and K mixers, where K is an integer greater than or equal to 2. In the figure, K=4 is taken as an example, and the K mixers are mixer 42121, mixer 42122, mixer 42123 and mixer 42124. The input end of the fourth beam splitter 4211 is the input end of the receiving component 421, and is used to obtain the local oscillator signal S 4 The four output ends of the fourth beam splitter 4211 are respectively connected to the four first input ends of the four mixers 42121 to 42124, and the four second input ends of the four mixers 42121 to 42124 are connected to the four receiving ends of the chip. 1 、c 2 、c 3 and c 4Here, the connection between the various components can be achieved through waveguides, optical fibers or other methods that can transmit optical signals. Fig.11a Take waveguide connection as an example.

[0168] Based on this structure and connection relationship, the input end of the fourth beam splitter 4211 can receive the dual-wavelength local oscillator signal S 4 The fourth beam splitter 4211 converts the dual-wavelength local oscillator signal S 4 Splitting (e.g., equal power splitting) into four dual-wavelength sub-LO signals S 41 , S 42 , S 43 , S 44 , and transmits these four dual-wavelength sub-local oscillator signals S through its four output ports. 41 ~S 44 The four mixers 42121 to 42124 can also receive the four receiving terminals of the chip. 1 ~c 4 Receive four echo signals S 51 , S 52 , S 53 , S 54 Each mixer performs a mixing operation on the received echo signal having the same wavelength as the dual-wavelength sub-local oscillator signal to generate its own intermediate frequency signal. The four intermediate frequency signals generated by the four mixers 42121 to 42124 jointly realize the target measurement.

[0169] Optionally, the four mixers 42121-42124 are combined with subsequent components to achieve the target measurement. Fig.10a and Fig.11a As shown, the receiving component 421 may also include a detection element 4213, which is connected between the output ends of the four mixers 42121-42124 and the electrical output end d of the chip, and is used to perform photoelectric detection on the four intermediate frequency signals generated by the four mixers 42121-42124, obtain an electrical signal, and output it. The electrical signal is transmitted to subsequent elements, such as an electrical chip, through the electrical output end d of the chip, and the intermediate frequency signal is processed in the electrical chip to obtain point cloud data and determine the distance and / or speed of the target.

[0170] Fig.11a The structure of the receiving component 421 shown can also be directly analogized to the receiving component 422. For example, Fig.11a and the above Fig.10c , see Fig.11b, still taking K=4 as an example, the receiving component 421 includes a fourth beam splitter 4211 and four mixers 42121~42124. The input end of the fourth beam splitter 4211 is the input end of the receiving component 421, which is used to obtain the local oscillator signal S 14 The four output ends of the fourth beam splitter 4211 are respectively connected to the four first input ends of the four mixers 42121 to 42124, and the four second input ends of the four mixers 42121 to 42124 are connected to the four receiving ends of the chip. 11 、c 12 、c 13 and c 14 Similarly, the receiving component 422 includes a fourth beam splitter 4221 and four mixers, namely mixer 42221, mixer 42222, mixer 42223 and mixer 42224. The input end of the fourth beam splitter 4221 is the input end of the receiving component 422, which is used to obtain the local oscillator signal S 24 The four output ends of the fourth beam splitter 4221 are respectively connected to the four first input ends of the four mixers 42221~42224, and the four second input ends of the four mixers 42221~42224 are connected to the other four receiving ends of the chip c 21 、c 22 、c 23 and c 24 .

[0171] Based on the structure and connection relationship, it is assumed that the first optical signal S 11 is the first wavelength, then, in the receiving component 421, the input end of the fourth beam splitter 4211 can receive the local oscillator signal S of the first wavelength 14 The fourth beam splitter 4211 converts the first wavelength local oscillator signal S 14 Split (e.g., equally split) into four sub-local oscillator signals S of the first wavelength 141 , S 142 , S 143 , S 144 and transmits the four first wavelength sub-local oscillator signals S through its four output ports. 141 ~S 144 The four mixers 42121 to 42124 can also receive the four receiving terminals of the chip. 11 ~c 14 Receive four echo signals S 151 , S 152 , S 153 , S 154Each mixer performs a mixing operation on the signal of the first wavelength in the received echo signal and the sub-local oscillator signal to generate its own intermediate frequency signal. The four intermediate frequency signals generated by the four mixers 42121-42124 are all intermediate frequency signals of the first wavelength. In other words, they can indicate relevant information of the target at the measurement distance corresponding to the first wavelength, such as distance and / or speed.

[0172] Similarly, assuming that the first optical signal S 21 is the second wavelength, then, in the receiving component 422, the input end of the fourth beam splitter 4221 can receive the local oscillator signal S of the second wavelength 24 The fourth beam splitter 4221 converts the local oscillator signal S of the second wavelength 24 Split (e.g., equally split) into four sub-LO signals S of the second wavelength 241 , S 242 , S 243 , S 244 and transmits the four second wavelength sub-local oscillator signals S 241 ~S 244 The four mixers 42221 to 42224 can also receive the other four receiving terminals of the chip. 21 ~c 24 Receive four echo signals S 251 , S 252 , S 253 , S 254 Each mixer performs a mixing operation on the second wavelength signal in the received echo signal and the sub-local oscillator signal to generate its own intermediate frequency signal. The four intermediate frequency signals generated by the four mixers 42221-42224 are all intermediate frequency signals of the second wavelength. In other words, they can indicate relevant information of the target at the measurement distance corresponding to the second wavelength, such as distance and / or speed.

[0173] Optionally, the eight mixers 42121-42124, 42221-42224 can be combined with subsequent components to achieve target measurement. Fig.11b As shown, the waveguide structure may also include a detection element 423, which is connected between the output ends of the eight mixers 42121~42124, 42221~42224 and the electrical output end d of the chip, and is used to perform photoelectric detection on the eight intermediate frequency signals generated by the eight mixers 42121~42124, 42221~42224, obtain an electrical signal, and output it. The electrical signal is transmitted to subsequent elements, such as an electrical chip, through the electrical output end d of the chip, and the intermediate frequency signal is processed in the electrical chip to obtain point cloud data and determine the distance and / or speed of the target.

[0174] Based on the above implementation scheme 2, two transmitting components and one or two receiving components can be set in the waveguide structure, and the local oscillator signal of any receiving component can be separated from the relevant signal of any element in the transmitting component. Therefore, the waveguide structure has high flexibility and versatility and can be adapted to various detection occasions.

[0175] Implementation scheme three: includes N transmitting components.

[0176] See also Fig.12 , showing a schematic diagram of a waveguide structure provided by Implementation Example 3. In this example, the waveguide structure 400 includes N transmitting components, where N is an integer greater than or equal to 2. It can be understood that the above Implementation Example 2 is a special case of Implementation Example 3, that is, the structure when N=2 in Implementation Example 3.

[0177] like Fig.12 As shown, each of the N transmitting components includes the EC, the first waveguide and the second waveguide described above. Fig.12 As shown, from top to bottom, the first transmitting component includes EC 4111, the first waveguide 4112 and the second waveguide 4113, the second transmitting component includes EC 4121, the first waveguide 4122 and the second waveguide 4123, ..., the Nth transmitting module includes EC 41N1, the first waveguide 41N2 and the second waveguide 41N3. In this case, the waveguide structure 400 also includes a first beam combiner 431 and a second beam combiner 432, and the first beam combiner 431 and the second beam splitter 432 both have N input ends and at least two output ends, and two output ends are taken as an example in the figure. The N input ends of the first beam combiner 431 are respectively connected to the output ends of the N first waveguides 4112~41N2 in the N transmitting components, and the two output ends of the first beam combiner 431 are connected to the two first transmitting ends b of the chip. 1 , b 2 The N input ends of the second beam combiner / splitter 432 are respectively connected to the output ends of the N second waveguides 4113 to 41N3 in the N transmitting components, and the two output ends of the second beam combiner / splitter 432 are connected to the two second transmitting ends b of the chip. 3 , b 4 .

[0178] Optionally, the N first optical signals S received by the N transmitting modules 11 ~S N1 In each transmitting component, EC splits the input single-wavelength first optical signal into a single-wavelength second optical signal and a third optical signal. The single-wavelength second optical signal is transmitted to the first beam combiner 431 through the first waveguide, and the single-wavelength third optical signal is transmitted to the second beam combiner 432 through the second waveguide. The first beam combiner 431 combines the input N wavelength second optical signals S12 ~S N2 After being combined into one beam, two first emission signals are split and emitted. Both first emission signals are optical signals of N wavelengths. The two first emission signals of N wavelengths are emitted from the two first emission terminals b and b of the chip respectively. 1 , b 2 Similarly, the second beam combiner / splitter 432 receives the input N wavelengths of the third optical signal S 13 ~S N3 After being combined into one beam, two second emission signals are split again. The two second emission signals are also N-wavelength optical signals. The two N-wavelength second emission signals are transmitted from the two second emission terminals b of the chip. 3 , b 4 The two first transmission signals and the two second transmission signals are scanned by the scanning component to the detection space for jointly measuring the target in the detection space.

[0179] Or, the N first optical signals S received by the N transmitting modules 11 ~S N1 It can also be the same wavelength but with different linear polarization states, or the same wavelength and the same linear polarization state, but different polarization elements are used to distinguish the corresponding echo signals, or some of the first optical signals are different wavelengths, and other first optical signals are the same wavelength but have different linear polarization states, or some of the first optical signals are the same wavelength but have different linear polarization states, and other first optical signals have the same wavelength and the same linear polarization state but the echo signals are distinguished by polarization elements, etc. There are many possible implementation methods, which are not specifically limited here.

[0180] Optionally, similar to the above embodiment 2, the waveguide structure 400 may further include one or more receiving components. The local oscillator signal of each receiving component may be separated from an input signal, a transmitted signal or an output signal of an element in the N ECs 4111~41N1, the N first waveguides 4112~41N2, the N second waveguides 4113~41N3, the first beam combiner 431, the second beam combiner 432, the waveguide after the first beam combiner 431, and the waveguide after the second beam combiner 432. For example:

[0181] In one example, Fig.13a The waveguide structure 400 includes a receiving component, which is shown in FIG. 4 Taking the signal transmitted by the second beam combiner / splitter 432 as an example, the scheme of separating from the first beam combiner / splitter 431 can be obtained by analogy with the figure. In this example, the second beam combiner / splitter 432 also has a third output terminal, which is connected to the receiving module 421. The second beam combiner / splitter 432 can also separate the local oscillator signal S of N wavelengths from the synthesized beam signal of N wavelengths.4 , the N-wavelength local oscillator signal S 4 Entering the receiving module 421, mixing with the echo signal received by the receiving end c of the chip on N wavelengths to obtain an intermediate frequency signal;

[0182] In another example, Fig.13b The structure diagram of the waveguide structure 400 includes N receiving components. The figure shows N local oscillator signals S 14 , S 24 ,……,S N4 Take the example of separating from the input signals of EC 4111, EC 4121, ..., EC 41N1 respectively. In this example, the N receiving components are receiving component 421, receiving component 422, ..., receiving component 42N respectively, and the N receiving components 421~42N correspond one-to-one to the N EC 4111~EC 41N1. Each EC in the N EC 4111~41N1 also has a third output end, and the third output end of each EC is connected to the corresponding receiving component. Each EC can also separate a single-wavelength local oscillator signal from the input single-wavelength first optical signal and transmit it to the connected receiving module. The single-wavelength local oscillator signal is mixed with the received echo signal on a single wavelength in the receiving component to obtain an intermediate frequency signal. When the first optical signal S S input in the N EC 4111~41N1 11 ~S N1 When there are N wavelengths, N local oscillator signals S 14 ~S N4 It also has N wavelengths. Each local oscillator signal is a single wavelength. Each receiving component only mixes the signal with the same wavelength as the local oscillator signal in the echo signal it receives, and the signals of other wavelengths can be discarded.

[0183] In another example, Fig.13c The waveguide structure 400 includes another structure diagram of N receiving components 421-42N. The figure is based on N local oscillator signals S 14 , S 24 ,……,S N4Take the example of separating the signals transmitted by any waveguide after EC 4111~EC 41N1 respectively. In this example, the waveguide structure 400 also includes N splitting elements. The figure takes N directional couplers 431, 432, ..., 43N as an example. The N directional couplers 431~43N correspond one-to-one to the N receiving components 421~42N. Each directional coupler can be coupled between the first waveguide of any transmitting component and the input end of the corresponding receiving component, or coupled between the second waveguide of any transmitting component and the input end of the corresponding receiving component. Each directional coupler is used to split a single-wavelength local oscillator signal from a single-wavelength optical signal transmitted in the coupled first waveguide or second waveguide, and output the single-wavelength local oscillator signal to the coupled receiving component. The single-wavelength local oscillator signal is mixed with the received echo signal on a single wavelength in the receiving component to obtain an intermediate frequency signal. When the first optical signal S input into the N ECs 4111~41N1 11 ~S N1 When there are N wavelengths, N receiving components can mix to obtain intermediate frequency signals corresponding to the N wavelengths.

[0184] Based on the above implementation scheme three, N transmitting components and one or N receiving components can be set in the waveguide structure. When one receiving component is set, the local oscillator signal of the receiving component can be separated from the combined optical signal, and the local oscillator signal is a multi-wavelength signal. When N receiving components are set, the local oscillator signal of each receiving component can be separated from the relevant signal of a transmitting component, and the local oscillator signals of the N receiving components are all single-wavelength signals with different wavelengths. The waveguide structure has high flexibility and versatility and can be adapted to various detection occasions.

[0185] It can be understood that, for the various embodiments introduced above, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between different embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form a new embodiment according to their internal logical relationships.

[0186] Furthermore, some modifications may be made to the above implementation schemes to form new implementation schemes. For example, in another example, more than N receiving components may be set in the above implementation scheme three. For example, a local oscillator signal may be separated from each first waveguide and each second waveguide. In this way, there will be 2N local oscillator signals, and correspondingly, 2N receiving components are set. Alternatively, the local oscillator signal is separated from the first waveguide and the second waveguide connected to part of the same EC to form any number of local oscillator signals greater than N but less than 2N, and the same number of receiving components are set. Alternatively, other optical splitting elements besides directional couplers and beam splitters may be used to achieve the effect of separating local oscillator signals. And so on, which will not be listed one by one here.

[0187] The waveguide structure provided in the above content can be applied to chips, such as silicon photonic chips, specifically, SOI silicon photonic chips.

[0188] See also Fig.14 , showing a possible structural schematic diagram of a silicon photonic chip provided by the present application. The silicon photonic chip 1400 includes a waveguide structure, and the waveguide structure can be any of the waveguide structures described above, such as the above Figure 4 , Figure 6 , Figure 7a~Figure 7d , Figure 8 , Fig. 9 , Figure 10a~10d , Figure 11a~Figure 11b , Fig.12 , Figure 13a~Figure 13c The waveguide structure 400 in any of the accompanying drawings.

[0189] Optionally, when the silicon photonic chip 1400 is a SOI silicon photonic chip, Fig.14 As shown, it may include a silicon substrate layer, a buried oxide layer and a top oxide layer stacked in sequence (for example, stacked from bottom to top as shown in the figure), the waveguide structure is buried in the top oxide layer, and the bottom contacts the buried oxide layer.

[0190] In some scenarios, the layer where the waveguide structure is located may also be called a waveguide layer, and the waveguide layer is a layer buried in the top oxide layer and composed of a waveguide material. In this case, the silicon photonic chip 1400 includes a silicon substrate layer, a buried oxide layer, a waveguide layer, and a top oxide layer stacked in sequence, and the waveguide structure is located in the waveguide layer.

[0191] The above silicon photonic chip 1400 can be applied to a detection device or system with a frequency modulation function, such as the FMCW LiDAR mentioned above, or an optical frequency domain reflectometry (OFDR) system, an optical coherence tomography (OCT) system, etc., without specific limitation.

[0192] See also Fig.15 , showing a possible structural schematic diagram of a detection device provided by the present application. The detection device 1500 may include the waveguide structure introduced in the above content, or may include the above silicon photonic chip 1400, such as Fig.15 shown.

[0193] Alternatively, if Fig.15As shown, the detection device 1510 may also include a light source component 1510, which is used to emit an optical signal. The optical signal is coupled into the waveguide structure through the EC at the edge of the silicon photonic chip 1400, and is emitted from the emission end of the silicon photonic chip 1400 after being transmitted through the emission component on the waveguide structure.

[0194] Alternatively, if Fig.15 As shown, the detection device 1500 also includes a scanning component 1520, and the scanning component 1520 is used to scan the optical signal emitted from the transmitting end of the silicon photonic chip 1400 to the detection space. After the optical signal is irradiated to the target in the detection space, it is reflected by the target to form an echo signal. Optionally, the echo signal can also be scanned to the receiving end of the silicon photonic chip 1400 through the scanning component 1520. An EC can also be set on the edge of the receiving end of the silicon photonic chip 1400, and the echo signal is coupled to the waveguide structure of the silicon photonic chip 1400 through the EC. After being mixed with the local oscillator signal by the receiving component in the waveguide structure, an intermediate frequency signal is generated, which is then converted into an electrical signal and output from the electrical output end of the silicon photonic chip 1400.

[0195] Further, optionally, if Fig.15 As shown, the detection device 1500 also includes a processing component 1531, which is arranged on the electrical chip 1530. The input end of the electrical chip 1530 is connected between the electrical output end of the silicon photonic chip 1400 and the input end of the processing component 1531. Therefore, the electrical signal output from the electrical output end of the silicon photonic chip 1400 is transmitted to the processing component 1531, and the processing component 1531 performs target detection according to the electrical signal, such as determining the distance and / or speed of the target.

[0196] Further, optionally, other components, such as an amplifier and an analog-to-digital converter (not shown in the figure), may be provided in the electrical chip 1530. The input end of the amplifier is connected to the electrical output end of the silicon photonic chip 1400, and the analog-to-digital converter is connected between the output end of the amplifier and the input end of the processing component 1531. The amplifier is used to amplify the electrical signal output by the silicon photonic chip 1400, and the analog-to-digital converter is used to perform discrete processing on the amplified electrical signal, convert it into a digital signal and output it to the processing component 1531, so that the processing component 1531 can detect the target according to the digital signal.

[0197] Optionally, as above Fig.15 As shown, the detection device 1500 may further include a window 1540 , which is used to protect various components inside the detection device 1500 and can transmit the optical signal emitted by the detection device 1500 .

[0198] It should be noted that Fig.15The detection device architecture given is only an example. In other examples, the detection device may include more, fewer, or different structures, and each structure may include more, fewer, or different components. This application does not make specific limitations on this.

[0199] Based on the structure and functional principle of the detection device described above, the present application can also provide a terminal device, see Fig.16 The terminal device 1600 may include the silicon photonic chip described above, or may include the above detection device 1500, such as Fig.16 shown.

[0200] Optional, such as Fig.16 As shown, the terminal device 1600 may also include a processor 1610, and the processor 1610 is used to call a program or instruction to control the above-mentioned detection device 1500 to work. Further, the processor 1610 may also receive the associated information of the target from the detection device 1500. When the terminal device 1600 is a vehicle, the processor 1610 may also perform path planning, braking or starting of the vehicle according to the acquired information. For example, the longitude and latitude may be used to determine the position of the vehicle, or the speed and direction may be used to determine the driving direction and destination of the vehicle in the future, or the distance of the surrounding objects may be used to determine the number and density of obstacles around the vehicle.

[0201] Further, optionally, the terminal device 1600 may also include a memory 1620, and the memory 1620 is used to store programs or instructions. Of course, the terminal device 1600 may also include other devices, such as a wireless communication device.

[0202] The processor 1610 may include one or more processing units. For example, the processor 1610 may include an application processor (AP), an image signal processor (ISP), a controller, a DSP, or other programmable logic devices, transistor logic devices, hardware components, or any combination thereof, etc. Different processing units may be independent devices or integrated into one or more processors.

[0203] The memory 1620 includes, but is not limited to, random access memory (RAM), flash memory, read-only memory (ROM), programmable ROM (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, mobile hard disks, CD-ROMs, or any other form of storage medium known in the art. Exemplarily, the storage medium is coupled to the processor so that the processor can read information from the storage medium and write information to the storage medium. Of course, the storage medium can also be a component of the processor. The processor and the storage medium can be located in an ASIC.

[0204] Exemplarily, the above terminal device 1600 can be, for example, a vehicle (such as an unmanned vehicle, a smart vehicle, an electric vehicle, or a digital car, etc.), a robot, a surveying and mapping equipment, a drone, a smart home device (such as a television, a sweeping robot, a smart desk lamp, an audio system, a smart lighting system, an electrical appliance control system, home background music, a home theater system, an intercom system, or video surveillance, etc.), smart manufacturing equipment (such as industrial equipment), smart transportation equipment (such as AGV, an unmanned transport vehicle, or a truck, etc.), or a smart terminal (a mobile phone, a computer, a tablet computer, a PDA, a desktop computer, headphones, audio, wearable devices, vehicle-mounted devices, virtual reality devices, augmented reality devices, etc.), etc.

[0205] It should be noted that, with the development of detection technology, the coherent calibration device structure provided in this application is also applicable to the same technical problems, and this application does not make any specific limitations on this.

[0206] In the above, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. In the text description of this application, the character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0207] In addition, in this application, the word "optionally" or "exemplary" is used to indicate an example, illustration or description. Any embodiment or design described as "optional" or "exemplary" in this application should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Alternatively, it can be understood that the use of the word "exemplary" or "optional" is intended to present concepts in a specific way and does not constitute a limitation on this application.

[0208] It is to be understood that the various digital numbers involved in the present application are only for the convenience of description and are not intended to limit the scope of the embodiments of the present application. The size of the sequence number of the above-mentioned processes does not mean the order of execution, and the order of execution of each process should be determined by its function and inherent logic. The terms "first", "second", "third" and similar expressions are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, including a series of steps or units. Methods, systems, products or equipment are not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or equipment.

Claims

1. A waveguide structure, characterized in that: include: An end coupler, a first waveguide and a second waveguide, wherein the first waveguide is connected to a first output end of the end coupler, and the second waveguide is connected to a second output end of the end coupler; The input end of the end face coupler inputs a first optical signal, the first output end of the end face coupler outputs a second optical signal, and the second output end of the end face coupler outputs a third optical signal. The input end of the end face coupler has a first mode spot size, the first waveguide and the second waveguide both have a second mode spot size, and the first mode spot size is larger than the second mode spot size.

2. The structure according to claim 1, characterized in that The first waveguide and the second waveguide are both single-mode waveguides.

3. The structure according to claim 1 or 2, characterized in that: The optical power of the second optical signal is equal to the optical power of the third optical signal.

4. The structure according to claim 1 or 2, characterized in that: The waveguide structure further includes a first beam splitter and a second beam splitter, wherein the first beam splitter is connected between an output end of the first waveguide and at least two first emitting ends of a chip where the waveguide structure is located, and the second beam splitter is connected between an output end of the second waveguide and at least two second emitting ends of the chip; The first beam splitter is used to split at least two first transmission signals from the input optical signal; The second beam splitter is used to split at least two second transmission signals from the input optical signal; Among them, the at least two first transmission signals are emitted to the scanning component through the at least two first transmission ends, and the at least two second transmission signals are emitted to the scanning component through the at least two second transmission ends. The at least two first transmission signals and the at least two second transmission signals are scanned by the scanning component to the detection space for detecting targets.

5. The structure according to claim 4, characterized in that The waveguide structure also includes a receiving component; The receiving component is used to obtain a local oscillator signal and an echo signal, and mix the local oscillator signal and the echo signal to obtain an intermediate frequency signal, and the intermediate frequency signal is used to determine the speed and / or distance of the target; The local oscillator signal is separated from an input signal, a transmitted signal or an output signal of any one of the end coupler, the first waveguide, the second waveguide, the first beam splitter or the second beam splitter.

6. The structure according to claim 5, characterized in that The end face coupler also has a third output end, and the third output end outputs the local oscillation signal. The receiving component is connected between the third output end and the receiving end of the chip.

7. The structure according to claim 5, characterized in that The second beam splitter also has another output end, and the receiving component is connected between the other output end and the receiving end of the chip; The second beam splitter is further used to split the local oscillator signal from the input optical signal, and output the local oscillator signal to the receiving component through the other output end.

8. The structure according to claim 5, characterized in that The waveguide structure further includes a beam splitter element coupled between the second waveguide and an input end of the receiving component; The optical splitter element is used to split the third optical signal transmitted in the second waveguide into the local oscillator signal, and output the local oscillator signal to the receiving component.

9. The structure according to claim 8, characterized in that The light splitting element is a directional coupler or a beam splitter.

10. The structure according to claim 1 or 2, characterized in that: The end face coupler, the first waveguide and the second waveguide are located in a launch component, and the launch component has N, where N is an integer greater than or equal to 2; The waveguide structure further includes a first beam combiner / splitter and a second beam combiner / splitter, wherein the first beam combiner / splitter and the second beam combiner / splitter each have N input ends and at least two output ends; the N input ends of the first beam combiner / splitter are respectively connected to the output ends of the N first waveguides in the N transmitting components, and the at least two output ends of the first beam combiner / splitter are connected to at least two first transmitting ends of the chip where the waveguide structure is located; The N input ends of the second beam combiner / splitter are respectively connected to the output ends of the N second waveguides in the N transmitting components, and at least two output ends of the second beam combiner / splitter are connected to at least two second transmitting ends of the chip; The first beam combiner / splitter is used to combine the N input optical signals into one beam and then split it into at least two first transmission signals; The second beam combiner / splitter is used to combine the N input optical signals into one beam and then split it into at least two second transmission signals; Among them, the at least two first transmission signals are emitted to the scanning component through the at least two first transmission ends, and the at least two second transmission signals are emitted to the scanning component through the at least two second transmission ends. The at least two first transmission signals and the at least two second transmission signals are scanned by the scanning component to the detection space for detecting targets.

11. The structure according to claim 10, characterized in that The optical signals from the N transmitting components have different wavelengths and / or different polarization states.

12. The structure according to claim 10, characterized in that The waveguide structure also includes a receiving component; The receiving component is used to obtain a local oscillator signal and an echo signal, and mix the local oscillator signal and the echo signal to obtain an intermediate frequency signal, and the intermediate frequency signal is used to determine the speed and / or distance of the target; Wherein, the local oscillator signal is separated from the input signal, the transmitted signal or the output signal of any device in the end coupler of any transmitting component, the first waveguide of any transmitting component, the second waveguide of any transmitting component, the first combiner / splitter or the second combiner / splitter.

13. The structure according to claim 12, characterized in that There are N receiving components, and the N receiving components correspond one-to-one to the N transmitting components. The end face coupler in each transmitting component also has a third output end, and the third output end outputs the local oscillator signal. Each receiving component is connected between the third output end of the end face coupler in the corresponding transmitting component and a receiving end of the chip.

14. The structure according to claim 12, characterized in that The second beam combiner / splitter also has another output end, and the receiving component is connected between the other output end and the receiving end of the chip; The second beam combiner / splitter is further used to split the local oscillator signal from the combined optical signal, and output the local oscillator signal to the receiving component through the other output end.

15. The structure according to claim 12, characterized in that There are N receiving components, and the waveguide structure further includes N optical splitting elements, the N optical splitting elements correspond to the N transmitting components and the N receiving components one by one, and each optical splitting element is coupled between the first waveguide of the corresponding transmitting component and the input end of the corresponding receiving component, or is coupled between the second waveguide of the corresponding transmitting component and the input end of the corresponding N receiving components; The N optical splitting elements are used to split the local oscillator signal from the optical signal transmitted by the coupled first waveguide or the second waveguide, and output the local oscillator signal to the coupled receiving component.

16. The structure according to any one of claims 5 to 9 and 12 to 15, characterized in that The optical power of the local oscillator signal is smaller than the optical power of the second optical signal and the optical power of the third optical signal.

17. The structure according to any one of claims 5 to 9 and 12 to 15, characterized in that The receiving component includes a fourth beam splitter and K mixers, K is an integer greater than or equal to 2; the input end of the fourth beam splitter is used to receive the local oscillator signal, the K output ends of the fourth beam splitter are connected to the K first input ends of the K mixers, and the K second input ends of the K mixers are connected to the K receiving ends of the chip; The fourth beam splitter is used to split the local oscillator signal into K sub-local oscillator signals, and output the K sub-local oscillator signals to the K mixers; The K mixers are used to perform mixing operations on the K sub-local oscillator signals and the K echo signals received by the K receiving ends of the chip to obtain K intermediate frequency signals.

18. The structure according to claim 17, characterized in that The receiving component further includes a detection element, and the detection element is connected between the output ends of the K mixers and the electrical output end of the chip; The detection element is used to perform photoelectric detection on the K intermediate frequency signals, obtain electrical signals and output them.

19. A silicon photonic chip, characterized in that: Comprising the waveguide structure as claimed in any one of claims 1 to 18.

20. The silicon photonic chip according to claim 19, characterized in that: The silicon photonic chip comprises a silicon substrate layer, a buried oxide layer, a waveguide layer and a top oxide layer stacked in sequence, and the waveguide structure is located in the waveguide layer.

21. A detection device, characterized in that: Comprising the silicon photonic chip as described in claim 19 or 20.

22. The detection device according to claim 21, characterized in that Also included is a light source assembly; The light source assembly is used to transmit an optical signal to the silicon photonic chip, and the optical signal is coupled into the waveguide structure through the end face coupler.

23. The detection device according to claim 21 or 22, characterized in that Also included is a scanning component; The scanning component is used to scan the optical signal emitted by the silicon photonic chip to a detection space.

24. The detection device according to claim 21 or 22, characterized in that: Also included is a processing component, wherein the processing component is disposed on the electrical chip; The processing component is used to determine the distance and / or speed of the target based on the electrical signal output by the silicon photonic chip.

25. A terminal device, characterized in that: Comprising a detection device as claimed in any one of claims 21 to 24.

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