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

Abstract

A waveguide structure (400), a silicon optical chip, a detection apparatus (1500), and a terminal device, used for reducing transmission loss caused by a TPA effect in waveguides under high optical power. The waveguide structure (400) comprises an edge coupler (EC) (4111), a first waveguide (4112), and a second waveguide (4113); the first waveguide (4112) is connected to a first output end of the EC (4111); the second waveguide (4113) is connected to a second output end of the EC (4111); an input end of the EC (4111) has a first mode field diameter; the first waveguide (4112) and the second waveguide (4113) each have a second mode field diameter; and the first mode field diameter is greater than the second mode field diameter. An input of the EC (4111) is a large mode field diameter, and outputs of the EC (4111) are two small mode field diameters. The EC (4111) can directly split an input optical signal into two waveguides, so that the optical power in each waveguide is reduced, high optical power density is not prone to occurring in each waveguide, and thus a TPA effect is not prone to occurring, thereby solving the problem of large transmission loss caused by the TPA effect in waveguides under high optical power density.

Description

A waveguide structure, a silicon photonics chip, a detection device, and a terminal equipment.

[0001] Cross-reference to related applications

[0002] This application claims priority to Chinese Patent Application No. 202422853918.2, filed on November 22, 2024, entitled "A Waveguide Structure, Silicon Photonic Chip, Detection Device and Terminal Equipment", the entire contents of which are incorporated herein by reference. Technical Field

[0003] This application relates to the field of sensor technology, and in particular to lidar, waveguide structures and silicon photonic chips in lidar, which can be applied to, but is not limited to, the field of transportation control. Background Technology

[0004] Among silicon photonics chip manufacturing processes, silicon-on-insulator (SOI) technology is the most mature. This process achieves dielectric isolation between components in the chip by introducing a buried oxide layer (also known as an insulating layer) between the top silicon layer and the back substrate. Compared to silicon nitride (SiN) and programmable logic chips (PLCs), SOI silicon photonics chips have advantages such as small size, doping capability, support for active device integration such as photodiodes (PDs), high yield, and low cost.

[0005] Currently, the waveguides in SOI silicon photonics chips are called silicon optical waveguides. Due to silicon's high refractive index, it is generally transparent to light with wavelengths exceeding 1.1 μm. However, at high optical power densities, two photons with wavelengths exceeding 1.1 μm are absorbed, generating charge carriers. These charge carriers further absorb light, leading to increased transmission loss, higher temperature, and decreased reliability in the silicon optical waveguide. This phenomenon is called the two-photon absorption (TPA) effect in silicon optical waveguides. The TPA effect in silicon optical waveguides is positively correlated with the optical power density; the higher the optical power density, the stronger the TPA effect and the greater the transmission loss of the silicon optical waveguide.

[0006] Therefore, how to reduce the transmission loss caused by the TPA effect of waveguides at high optical power is a technical problem that urgently needs to be solved in the field of SOI silicon photonics chips. Summary of the Invention

[0007] This application provides a waveguide structure, a silicon photonics chip, a detection device, and a terminal device 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 photonics chip can withstand.

[0008] In a first aspect, this application provides a waveguide structure including an end-face coupler, a first waveguide, and a second waveguide. The first waveguide is connected to a first output terminal of the end-face coupler, and the second waveguide is connected to a second output terminal of the end-face coupler. A first optical signal is input to the input terminal of the end-face coupler, a second optical signal is output from the first output terminal of the end-face coupler, and a third optical signal is output from the second output terminal of the end-face coupler. The input terminal of the end-face coupler has a first mode size, and both the first waveguide and the second waveguide have a second mode size. The first mode size is larger than the second mode size.

[0009] Based on the waveguide structure described above, the input of the end-face coupler is a large mode size, and the output is two small mode sizes. Therefore, the end-face coupler can transform a large mode input into two small mode outputs. In this way, all optical power coupled into the end-face coupler is split into two waveguides, preventing all optical power from being concentrated in a single waveguide. This reduces the optical power transmitted in each waveguide, making it less prone to high optical power density. Consequently, when this waveguide structure is applied to SOI silicon photonics chips, the TPA effect is less likely to occur in each waveguide, solving the problem of high transmission loss caused by the TPA effect under high optical power density in SOI silicon photonics chips. Furthermore, this waveguide structure directly splits two optical signals through the end-face coupler, which, compared to existing technologies that use an end-face coupler and a beam splitter, saves on the number of beam splitters required, reducing cost and structural complexity. Furthermore, the waveguide structure described above is entirely made of passive components. Therefore, it can be formed directly through a single exposure without the need for additional semiconductor process steps, doping, power-on processes, or additional power consumption. It has the advantages of simple process, minimalist architecture, extremely low cost, extremely high performance, and extremely high reliability.

[0010] In one possible design, both the first and second waveguides are single-mode waveguides. Single-mode waveguides have a smaller cross-sectional size and transmit only a single mode internally, avoiding the problems of multiple modes and collision interference between multiple modes, thus exhibiting better optical transmission performance.

[0011] In one possible design, the optical power of the second optical signal is equal to the optical power of the third optical signal.

[0012] Based on the above design, the end-face coupler can split the first optical signal into a second optical signal and a third optical signal with equal power. 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 in each waveguide.

[0013] In one possible design, the end-face coupler, the first waveguide, and the second waveguide are located in the transmitting assembly. The transmitting assembly may also include other structures, mainly including the following structure one and structure two.

[0014] Structure 1: The transmitting component further 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 containing the waveguide structure. 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. The at least two first transmitting signals are emitted to the scanning component through the at least two first transmitting ends, and the at least two second transmitting signals are emitted to the scanning component through the at least two second transmitting ends. The at least two first transmitting signals and the at least two second transmitting signals are scanned into the detection space by the scanning component for target detection.

[0015] Based on the above structure one, a transmitting component can be set in the waveguide structure. This transmitting component emits at least four transmitted signals through at least four transmitting ends. These at least four transmitted signals can be used to jointly measure and detect targets in the detection space. For example, the at least four transmitted signals can correspond to at least four detection channels. In this way, at least four regions can be detected in a single scan, increasing the scanning range and improving detection efficiency.

[0016] In one example of structure one, the waveguide structure also includes a receiving component for acquiring the local oscillator signal and the echo signal, and mixing the local oscillator signal and the echo signal to obtain an intermediate frequency signal. The local oscillator signal is derived from the input signal, transmitted signal, or output signal of any of the end-face couplers, the first waveguide, the second waveguide, the first beamsplitter, or the second beamsplitter. The intermediate frequency signal is used to determine the velocity and / or distance of the target.

[0017] Based on the above examples, when there is one transmitting component, there is also one receiving component. 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 applications.

[0018] In the above example, the local oscillator signal in the receiving component can be separated using any of the following separation methods one to three:

[0019] In the first splitting method, the end-face coupler also has a third output terminal, which outputs the local oscillator signal. The receiving component is connected between the third output terminal and the receiving terminal of the chip. Based on this splitting method, the local oscillator signal can be separated from the input signal of the end-face coupler. The end-face coupler directly splits the input optical signal into three optical signals. Two of these optical signals are split into at least four transmission signals by a beam splitter, and the remaining optical signal is used as the local oscillator signal and mixed with the echo signal. In this way, with equal-power beam splitting by the beam splitter, at least four transmission signals have equal power, at least four detection channels emit light uniformly, and at least four transmission signals can reach the same distance in the detection space, thereby obtaining detection results for different regions at the same distance. This detection method has the best detection effect.

[0020] In the second beam splitting method, the second beam splitter also has another output terminal. The receiving component is connected between the other output terminal and the receiving terminal of the chip. 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 terminal. Based on this second beam splitting method, the local oscillator signal can be separated from the input signal of the second beam splitter. The second beam splitter splits the input optical signal into at least three optical signals, of which at least two optical signals are used as at least two transmitted signals, and the other optical signal is used as the local oscillator signal and mixed with the echo signal.

[0021] In the third separation method, the waveguide structure also includes a beam splitter. The beam splitter is coupled between the second waveguide and the input of the receiving component. The beam splitter is used to split the third optical signal transmitted in the second waveguide into a local oscillator signal, and then output the local oscillator signal to the receiving component. Based on this third separation method, the local oscillator signal can be separated from the signal transmitted in the second waveguide using the beam splitter. A portion of the optical signal transmitted in the second waveguide is separated as the local oscillator signal, and the remainder is split into at least two transmitted signals by the second beam splitter.

[0022] In one example of the above beam splitting method three, the beam splitting element can be a directional coupler or a beam splitter.

[0023] Based on the above examples, a directional coupler can couple the local oscillator signal from the second waveguide in a non-contact manner, while a 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 beam splitting elements, improving flexibility and versatility.

[0024] Structure 2: There are N transmitting components, where N is an integer greater than or equal to 2. In this case, the waveguide structure also includes a first beam combiner / splitter and a second beam combiner / splitter. Both the first beam combiner / splitter and the second beam splitter have N input terminals and at least two output terminals. The N input terminals of the first beam combiner / splitter are respectively connected to the output terminals of the N first waveguides in the N transmitting components, and the at least two output terminals of the first beam combiner / splitter are connected to at least two first transmitting terminals of the chip containing the waveguide structure. The N input terminals of the second beam combiner / splitter are respectively connected to the output terminals of the N second waveguides in the N transmitting components, and the at least two output terminals of the second beam combiner / splitter are connected to at least two first transmitting terminals of the chip containing the waveguide structure. Each output terminal is connected to at least two second transmitting terminals of the chip; a first beam combiner / splitter is used to combine N input optical signals into one beam and then split the light into at least two first transmitting signals, and a second beam combiner / splitter is used to combine N input optical signals into one beam and then split the light 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 terminals, at least two second transmitting signals are emitted to the scanning component through at least two second transmitting terminals, and at least two first transmitting signals and at least two second transmitting signals are scanned to the detection space by the scanning component for the purpose of detecting targets.

[0025] Based on structure two above, N transmitting components can be set in the waveguide structure. The optical signals emitted by the N transmitting components are combined into at least four transmitted signals by two beam combiners and splitters. These at least four transmitted signals can be used to jointly measure and detect targets in the detection space. For example, at least four transmitted signals can correspond to at least four detection channels. In this way, at least four regions can be detected in a single scan, increasing the scanning range and improving detection efficiency.

[0026] In one example of structure two, optical signals from N emitting components have different wavelengths and / or different polarization states.

[0027] Based on the above examples, if different wavelengths are used, each transmitted signal has N wavelengths, and N wavelengths correspond to different detection distances. Therefore, each transmitted signal can detect more distances, improving the comprehensiveness of detection. If different polarization states are used, multiple signals of the same wavelength can be used to detect the same distance, thereby improving detection accuracy.

[0028] In one example of Structure 2, the waveguide structure further includes a receiving component for acquiring the local oscillator signal and the echo signal, and mixing the local oscillator signal and the echo signal to obtain an intermediate frequency (IF) signal. The local oscillator signal is derived from the input signal, transmitted signal, or output signal of any of the following devices: the end-face coupler of any transmitting component, the first waveguide of any transmitting component, the second waveguide of any transmitting component, the first beam combiner / splitter, or the second beam combiner / splitter. The IF signal is used to determine the velocity and / or distance of the target.

[0029] Based on the above examples, when there are multiple transmitting components, there may be one or more receiving components. The local oscillator signal of the one or more receiving components can be separated from the related signals of the elements of any of the multiple transmitting components. Therefore, the waveguide structure has high flexibility and versatility and can be adapted to various detection applications.

[0030] In the above example, the local oscillator signal in the receiving component can be separated using any of the following separation methods one to three:

[0031] In the first splitting method, there are N receiving components, each corresponding one-to-one with one of the N transmitting components. Each of the N end-face couplers in the N transmitting components has a third output terminal, used to output the local oscillator signal. Each receiving component is connected between the third output terminal of the end-face coupler in its corresponding transmitting component and a receiving terminal of the chip. Based on this splitting method, with N receiving components, the local oscillator signals of each of the N receiving components are derived from the input signals of the end-face couplers of the N transmitting components. These N local oscillator signals have different wavelengths, each being a single-wavelength signal; therefore, the mixing process also involves mixing single-wavelength signals. Furthermore, when the beam combiner and splitter distributes the optical signals equally, at least four transmitting signals have equal power, and at least four detection channels produce uniform light output.

[0032] In the second separation method, the second beam combiner / splitter also has another output terminal. The receiving component is connected between the other output terminal and the receiving terminal of the chip. The second beam combiner / splitter is also used to separate the local oscillator signal from the combined optical signal and output the local oscillator signal to the receiving component through the other output terminal. Based on this separation method, there can be only one receiving component. The local oscillator signal of the receiving component is separated from the input signal of any beam combiner / splitter. The local oscillator signal is an N-wavelength signal, and the mixing operation is a first mixing of the N-wavelength signal.

[0033] In the third separation method, there are N receiving components, and the waveguide structure also includes N beam-splitting elements. These N beam-splitting elements correspond one-to-one with the N transmitting components and the N receiving components. Each beam-splitting element is coupled between the first waveguide of its corresponding transmitting component and the input terminal of its corresponding receiving component, or between the second waveguide of its corresponding transmitting component and the input terminals of its corresponding N receiving components. The N beam-splitting elements are used to separate the local oscillator signal from the optical signal transmitted through the coupled first or second waveguide and output the local oscillator signal to the coupled receiving component. Based on this third separation method, there are N receiving components, and the local oscillator signal of each receiving component can be separated from the signal transmitted through the waveguide of one transmitting component. The separation method can be through coupling via a directional coupler or beam splitting via a beam splitter. The local oscillator signals of the N receiving components are all single-wavelength signals with different wavelengths.

[0034] In one example of structure one or structure two above, 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.

[0035] Based on this example, the local oscillator signal can have a smaller optical power to reduce the impact on the power of the transmitted signal and increase the detection range of the transmitted power.

[0036] In one example of Structure 1 or Structure 2 above, the receiving component includes a fourth beam splitter and K mixers, where K is an integer greater than or equal to 2. The input of the fourth beam splitter is used to receive the local oscillator signal, the K outputs of the fourth beam splitter are connected to the K first inputs of the K mixers, and the K second inputs of the K mixers are connected to the K receiving terminals 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 a mixing operation on the K sub-local oscillator signals and the K echo signals received by the K receiving terminals of the chip to obtain K intermediate frequency signals.

[0037] Based on the above example, the reception range of the echo signal can be increased by using K receiving paths. Even if the echo signal is deviated from a certain distance, the probability of receiving the echo signal can be increased, thereby improving the reception efficiency.

[0038] In a further possible example, the receiving component also includes a detection element connected between the outputs of the K mixers and the electrical output of the chip. The detection element is used to perform photoelectric detection on the K intermediate frequency signals, obtain electrical signals, and output them.

[0039] Based on the above examples, the conversion from optical signals to electrical signals can be realized, thereby enabling the transmission of silicon photonic signals to electrical chips.

[0040] Secondly, this application provides a silicon photonics chip, including the waveguide structure described in the first aspect, any of the designs or examples above.

[0041] In one possible design, the silicon photonics chip includes a silicon substrate layer, a buried oxide layer, a waveguide layer, and a top oxide layer stacked sequentially, with the waveguide structure located in the waveguide layer.

[0042] Based on the above design, silicon photonics chips can have advantages such as small size, doping capability, support for active device integration, high yield, and low cost.

[0043] Thirdly, this application provides a detection device, including the waveguide structure in the first aspect or any of the designs or examples of the first aspect, or including the silicon photonic chip in the second aspect or any of the designs of the second aspect.

[0044] In one possible design, the detection device also includes a light source assembly for emitting optical signals to the silicon photonic chip, which are coupled into the waveguide structure via an end-face coupler.

[0045] In one possible design, the detection device also includes a scanning component for scanning the optical signal emitted from the silicon photonics chip into the detection space.

[0046] In one possible design, the detection device also includes a processing component disposed on the electrical chip, which is used to determine the distance and / or velocity of the target based on the electrical signal output by the silicon photonics chip.

[0047] Fourthly, this application provides a terminal device that includes the waveguide structure in the first aspect or any of the designs or examples of the first aspect, or includes the silicon photonic chip in the second aspect or any of the designs of the second aspect, or includes the detection device in the third aspect or any of the designs of the third aspect.

[0048] The technical effects that can be achieved in the second to fourth aspects mentioned above can be referred to the description of the beneficial effects in the first aspect mentioned above, and will not be repeated here. Attached Figure Description

[0049] Figure 1 illustrates a possible application scenario to which this application applies;

[0050] Figure 2a illustrates an exemplary architecture diagram of a mainstream FMCWLiDAR.

[0051] Figure 2b illustrates, for example, the optical power transmission of silicon photonics chips in mainstream FMCWLiDAR.

[0052] Figure 3 illustrates an exemplary structural diagram of a solution to the TPA effect in silicon photonics chips provided by the industry.

[0053] Figure 4 illustrates a schematic diagram of a waveguide structure provided in this application;

[0054] Figure 5a illustrates a possible structural diagram of an end-face coupler provided in this application;

[0055] Figure 5b illustrates an exemplary schematic diagram of optical power transmission of an end-face coupler provided in this application;

[0056] Figure 6 illustrates a schematic diagram of a waveguide structure provided in Implementation Scheme 1.

[0057] Figure 7a is an exemplary schematic diagram of a structure for separating the local oscillator signal from the input signal of the end face coupler according to Embodiment 1;

[0058] Figure 7b is an exemplary schematic diagram of a structure for separating a local oscillator signal from the input signal of a beam splitter according to Embodiment 1;

[0059] Figure 7c is an exemplary schematic diagram of a structure for separating a local oscillator signal from a signal transmitted through a waveguide, provided in Embodiment 1.

[0060] Figure 7d illustrates an exemplary schematic diagram of another structure for extracting the local oscillator signal from the signal transmitted through the waveguide, provided in Implementation Scheme 1.

[0061] Figure 8 illustrates a schematic diagram of the structure of a receiving component provided in Implementation Scheme 1;

[0062] Figure 9 illustrates a schematic diagram of a waveguide structure provided in Scheme 2;

[0063] Figure 10a is an exemplary schematic diagram of a structure for separating a local oscillator signal from a signal transmitted by a beam combiner / splitter according to embodiment two.

[0064] Figure 10b illustrates an exemplary schematic diagram of a structure for separating a local oscillator signal from the input signal of an end-face coupler according to Embodiment 2.

[0065] Figure 10c exemplarily illustrates a schematic diagram of a structure for separating a local oscillator signal from a signal transmitted through a waveguide, according to Embodiment 2.

[0066] Figure 10d illustrates an exemplary schematic diagram of another structure for separating the local oscillator signal from the signal transmitted in the waveguide, provided by Implementation Scheme 2.

[0067] Figure 11a illustrates a schematic diagram of a receiving component provided in Embodiment 2;

[0068] Figure 11b illustrates a schematic diagram of another receiving component provided in Implementation Scheme 2;

[0069] Figure 12 illustrates a schematic diagram of a waveguide structure provided in Embodiment 3;

[0070] Figure 13a is an exemplary schematic diagram of a waveguide structure including a receiving component provided in Embodiment 3;

[0071] Figure 13b is an exemplary schematic diagram of a waveguide structure including N receiving components provided in Implementation Scheme 3;

[0072] Figure 13c exemplarily illustrates a structural schematic diagram of another waveguide structure provided in Scheme 3, which includes N receiving components;

[0073] Figure 14 illustrates a possible structural diagram of a silicon photonics chip provided in this application;

[0074] Figure 15 illustrates a possible structural diagram of a detection device provided in this application;

[0075] Figure 16 illustrates a schematic diagram of the structure of a terminal device provided in this application. Detailed Implementation

[0076] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0077] The following provides explanations for some of the terms used in this application. It should be noted that these explanations are for the convenience of those skilled in the art and do not constitute a limitation on the scope of protection claimed in this application.

[0078] I. Silicon-on-insulator (SOI)

[0079] SOI is a technique for growing semiconductor thin films on an insulating substrate. It introduces a buried oxide layer between the top silicon layer and the back substrate, effectively isolating current leakage and mutual interference between different parts of the chip, thus improving device performance and reliability. Chips fabricated using SOI technology offer advantages such as high speed, low power consumption, high reliability, and resistance to high temperatures and pressures.

[0080] II. Two-photon absorption (SPA) effect

[0081] The two-photon absorption (SPA) effect refers to the simultaneous absorption of two photons by a molecule, causing it to transition from its ground state to an excited state via a virtual energy level. The absorption intensity is proportional to the square of the light intensity. The SPA effect occurs only under strong light and is a type of third-order nonlinear effect. For example, in lidar, the SPA effect is mainly concentrated at the focal point of the ultra-intense laser generated by the laser, while the laser intensity elsewhere in the optical path is insufficient to produce two-photon absorption. Simply put, if the ultra-intense laser generated by the laser is focused onto the same single-mode waveguide of an SOI silicon photonics chip, that single-mode waveguide will exhibit a very strong SPA effect. A large amount of the optical signal in this single-mode waveguide will be absorbed, resulting in a reduced output signal and significant transmission loss.

[0082] III. Single-mode waveguide

[0083] A single-mode waveguide is a waveguide in which light can propagate in only one mode. This propagation mode is called the fundamental mode. Therefore, it can also be considered that only the fundamental mode of light is transmitted in a single-mode waveguide, while all higher-order modes of the light wave are cut off. Different types of waveguides can have different single-mode conditions. Achieving the single-mode condition can avoid multimode interference and signal distortion, making waveguide transmission more stable and reliable.

[0084] IV. Edge Coupler (EC)

[0085] An EC (electrode coupling) is a coupler located at the edge of an optical chip, used to couple single-mode waveguides to optical devices (such as lasers, modulators, or high-speed detectors). More specifically, it can couple single-mode waveguides to single-mode optical fibers. Typically, the mode field diameter (MFD) of a single-mode waveguide and the MFD of a single-mode optical fiber do not perfectly match. For example, for silicon photonic chips, the MFD of a single-mode waveguide is 0.4-0.5 μm, while the MFD of a single-mode optical fiber is 9-10 μm, a significant difference. Direct coupling would result in a coupling loss of approximately -20 dB. Using an EC to couple the two devices allows for mode field matching, achieving higher coupling efficiency.

[0086] V. Pattern

[0087] A mode spot, also known as a mode field, refers to the electric field distribution that a waveguide cross-section can support. The parameter that measures this 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.

[0088] VI. Linear Polarization State

[0089] Linear polarization is a mode of light propagation. Light exhibiting linear polarization is called linearly polarized light, also known as plane-polarized light. In the direction of light propagation, the electric vector at each point lies within a defined plane. Since the trajectory of the endpoints of the electric vector is a straight line, it is called linearly polarized light. The plane of vibration of linearly polarized light is fixed and does not deflect. The plane of vibration refers to the plane formed by the direction of the light vector and the direction of light propagation.

[0090] Common linearly polarized light includes P-waves, S-waves, TE-waves, and TM-waves. P-waves and S-waves represent light with different polarization directions in space. Simply put, in space, the light vector is decomposed into two mutually perpendicular vibration directions. The vibration direction within the plane of incidence is called the parallel component of the light vector, or P-wave, and the vibration direction perpendicular to the plane of incidence is called the perpendicular component, or S-wave. TE-waves and TM-waves represent light with different polarization directions from a chip integration perspective, often used to describe the propagation characteristics of electromagnetic waves. TE-waves are also called transverse electric waves, where the electric field component is perpendicular to the propagation direction of the electromagnetic wave; that is, the electric field component is parallel to the plane of incidence. TM-waves are also called transverse magnetic waves, where the magnetic field component is perpendicular to the propagation direction of the electromagnetic wave; that is, the electric field direction is perpendicular to the plane of incidence.

[0091] 7. Signal to Interference Plus Noise Ratio (SINR)

[0092] SINR is the ratio of the strength of the received useful signal to the strength of the received interference signal, which can be simply understood as the "signal-to-noise ratio". The interference signal includes both noise and interference.

[0093] 8. Frequency Mixing

[0094] Frequency mixing, also known as coherent demodulation, refers to the difference between the frequencies and phases of two signals. In FMCW LiDAR, the probe signal is typically a linear frequency modulated (LFM) signal. After this LFM signal interacts with the target object, the reflected echo signal (i.e., the received signal) will also have the same frequency variation characteristics. However, depending on the distance to the target, the echo signal will have a certain phase and frequency difference relative to the probe signal. Therefore, after receiving the echo signal, the echo signal and the probe signal can be mixed, that is, the frequency and phase of the probe signal and the echo signal are differed to obtain a low-frequency beat signal, also known as the beat frequency signal or intermediate frequency (IF) signal. The IF signal contains information about the frequency difference between the two signals, which is proportional to the target distance. It also contains information about the Doppler effect caused by the target's movement, based on which the target's velocity can be calculated.

[0095] The preceding text introduced some of the terms used in this application. The following text introduces the possible application scenarios of this application.

[0096] In one possible implementation, the waveguide structure provided in this application can be applied to a detection device installed on a vehicle, such as, but not limited to, vehicles, ships, airplanes, drones, trains, subways, automated guided vehicles (AGVs), or unmanned vehicles. For example, please refer to Figure 1, which illustrates a possible application scenario of this application. In this scenario, the detection device is installed on the front bumper of a vehicle. This detection device can serve as an information source for path planning, assisting the driver in achieving or automatically achieving safe driving. It is understood that the detection device can also be installed in other locations on the vehicle, such as around the headlights, around the rearview mirrors, near the doors, on the rear bumper, behind the windshield, or on the roof, to capture information about the vehicle's surrounding environment. When the detection device is installed behind the windshield, the requirement for no gravel collision risk is lower, and it does not affect the vehicle's appearance. Furthermore, the windshield itself has window heating and defogging functions as well as wiper cleaning functions.

[0097] It should be understood that the above application scenarios are merely examples, and the detection device provided in this application can also be applied to other possible scenarios, and is not limited to those exemplified above. For example, the detection device can also be installed in a roadside 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 alert the user to children or pets left behind in the cabin. Furthermore, the detection device can also be applied to terminal devices or components installed in terminal devices, such as smartphones, smart home devices, smart manufacturing equipment, medical devices, industrial equipment, and robots. These will not be listed exhaustively here. It should be noted that the application scenarios described in this application are for the purpose of more clearly illustrating the technical solution of this application and do not constitute a limitation on the technical solution provided in this application.

[0098] In addition, the above-mentioned application scenarios can be applied to fields such as autonomous driving, assisted driving, intelligent driving, autonomous driving, connected vehicles, optical communication, security monitoring, biomedicine, surveying and mapping (such as 3D mapping and remote sensing mapping), meteorological research, biomass and vegetation research, air quality monitoring, and aviation and aerospace applications.

[0099] The detection devices mentioned above may include, but are not limited to, light detection and ranging (LiDAR), such as frequency modulated continuous wave LiDAR (FMCWLiDAR). Before introducing the specific solution provided in this application, the relevant content of FMCW LiDAR will be introduced below.

[0100] Please refer to Figure 2a, which shows a schematic diagram of a mainstream FMCWLiDAR architecture. This architecture includes a laser, an SOI silicon photonics chip, and a scanning component. The laser and scanning component are located outside the SOI silicon photonics chip. The SOI silicon photonics chip contains an end-face coupler EC, beam splitter 1, beam splitter 21, and beam splitter 22, as well as single-mode waveguides connecting these components. For example, single-mode waveguide B1 connects EC and beam splitter 1, and single-mode waveguide B connects beam splitter 1 and beam splitter 21. 21 The single-mode waveguide B connecting beam splitter 1 and beam splitter 22 22 And the single-mode waveguide B connecting the beam splitters 21 and 22 to the four transmitters of the SOI silicon photonics chip, respectively. 31 B 32 B 33 and B 34It should be noted that the diagram only illustrates an SOI silicon photonics chip with four transmitters, but the actual number of transmitters can be any integer greater than or equal to two, and this application does not impose any specific limitation.

[0101] Taking the structure shown in Figure 2a as an example, the EC is located on the left edge (also called the left end face) of the SOI silicon photonic chip. The laser emits a laser signal S1 towards the left edge of the SOI silicon photonic chip. This laser signal S1 is coupled into the single-mode waveguide B1 through the EC, and then transmitted to the beam splitter 1 through the single-mode waveguide B1. The beam splitter 1 then splits the light into two sub-light signals. The two sub-light signals are then transmitted through the single-mode waveguide B1 and the EC to the single-mode waveguide B1. 21 and B 22 The light is transmitted to beam splitters 21 and 22, and further split by beam splitters 21 and 22 to form four sub-optical signals. The four sub-optical signals then pass through four single-mode waveguides B. 31 ~B 34 The signal is transmitted to the four transmitters of the SOI silicon photonics chip and emitted to the outside of the SOI silicon photonics chip. It is then illuminated to the target by the scanning component and reflected by the target to form an echo signal. This echo signal is used to measure the distance and / or speed of the target.

[0102] As shown in Figure 2a, after the optical signal is input to the left end face of the SOI silicon photonics chip, it is received by the EC (Electronic Coupling) located 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 transmission loss (also known as the transmission loss). When the coupling efficiency is not 100%, the optical power of the optical signal received by the EC is less than that of the optical signal input to the end face of the SOI silicon photonics chip. Given the inherent transmission loss of the EC, the optical power of the optical signal output by the EC is less than that of the optical signal received by the EC. Typically, the transmission loss of the EC 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.

[0103] In the scheme shown in Figure 2a, the optical signals output by the EC are all coupled to the single-mode waveguide B1. Ignoring the EC's own loss, all the optical power received by the EC enters the single-mode waveguide B1. In the SOI silicon photonics chip, the cross-sectional area of ​​the EC is larger than that of the single-mode waveguide B1. For a given optical power, the optical power density in the device is inversely proportional to the cross-sectional area. Therefore, the optical power density in the EC is lower than that in the single-mode waveguide B1. The single-mode waveguide B1 is the part of the SOI silicon photonics chip that bears the highest optical power density and is most prone to the TPA effect, as shown in Figure 2b. After passing through the single-mode waveguide B1, the optical signal is split into two single-mode waveguides B1. 21 B 22 Above, each single-mode waveguide B 21B 22 The optical power in the single-mode waveguide B1 is lower than that in the single-mode waveguide B1. Therefore, the single-mode waveguide B1... 21 B 22 The optical power density on the single-mode waveguide B1 is less than that on the single-mode waveguide B1. Similarly, the optical power density on the single-mode waveguide B1 is less than that on the single-mode waveguide B1. 31 ~B 34 The optical power density on the upper part is less than that of the single-mode waveguide B. 21 B 22 The optical power density on the first waveguide B1 is insufficient to produce the TPA effect. Therefore, the bottleneck of the TPA effect lies in the first waveguide B1.

[0104] As described in the background section, the TPA effect in silicon optical waveguides leads to problems such as increased transmission loss, higher temperature, and decreased reliability. Therefore, to mitigate these issues caused by the TPA effect in the first single-mode waveguide B1, an industry solution has been proposed, as shown in Figure 3. This solution designs the first single-mode waveguide B1 as a silicon ridge waveguide, adding P-doping and N-doping to its two sides respectively to form a PN junction. Simultaneously, a reverse bias voltage is applied to the PN junction. When a high-power optical signal passes through the first waveguide B1, the carriers generated by the TPA effect are extracted from the first waveguide B1 by the PN junction, maintaining a low carrier concentration in the first waveguide B1 and suppressing further absorption and heating of the optical signal by the carriers. In some scenarios, the extracted current can be measured to form an ammeter, allowing adjustment of the reverse bias voltage applied to the PN junction based on the real-time current signal to ensure that the first waveguide B1 maintains a low carrier concentration.

[0105] While the above solutions can remove carriers generated by the TPA effect through power application, they cannot prevent the TPA effect from occurring. Furthermore, they introduce other problems, primarily the following two: First, whether designing the first waveguide B1 as a ridge waveguide or doping it with P and N ions on both sides, the manufacturing process is complex and costly; second, applying power to the PN junction introduces additional power consumption and generates current-induced heating, raising reliability issues. Due to these problems, the above solutions offered by the industry have limited usability in FMCW LiDARs.

[0106] In view of this, this application provides a waveguide structure that directly splits the input optical signal into two waveguides using a large-mode EC (Electrical Envelope Array), thereby reducing the optical power density in each waveguide and lowering the probability of TPA (Transient Power Allocation) effect. Compared to industry-provided solutions, this waveguide structure is entirely passive, requiring no additional semiconductor processing steps, doping, or electrical discharge, and thus solving the problems associated with existing industry solutions. It offers advantages such as simple manufacturing process, low cost, low power consumption, and high reliability.

[0107] The waveguide structure and related schemes proposed in this application will be described in detail below with reference to Figures 4 to 16.

[0108] Please refer to Figure 4, which shows a schematic diagram of a waveguide structure provided in this application. The waveguide structure 400 includes EC 4111, a first waveguide 4112, and a second waveguide 4113. EC 4111 has an input terminal a. 11 First output terminal a 12 Second output terminal a 13 The first waveguide 4112 is connected to the first output terminal a of EC 4111. 12 The second waveguide 4113 is connected to the second output terminal a of EC 4111. 13 EC 4111 input terminal a 11 Input first optical signal S 11 EC 4111's first output terminal a 12 Output the second optical signal S 12 The third output terminal a of EC 4111 13 Output third optical signal S 13 Furthermore, the first optical signal S 11 The optical power is greater than that of the second optical signal S 12 Optical power and third optical signal S 13 The optical power. In one possible implementation, the input terminal a of EC 4111... 11 Both the first waveguide 4112 and the second waveguide 4113 have a first mode spot size, and the first mode spot size is larger than the second mode spot size.

[0109] Under ideal conditions (ignoring optical transmission loss), the first optical signal S 11 The optical power is equal to the second optical signal S 12 Optical power and third optical signal S 13 The sum of optical power. Wherein, the second optical signal S... 12 Optical power and third optical signal S 13The optical power of the two signals can be the same or different. For example, in one example, to effectively reduce the optical power density in each waveguide, the difference in optical power between the two signals can be configured to be less than a set value; in other words, the optical power of the two signals is the same or very close. Taking the same as an example, EC 4111 can couple the first optical signal S... 11 Equal power is 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 distributed into two waveguides 4112 and 4113, and the optical power density in each waveguide is only half that of the existing scheme, so that all the optical power is in one waveguide.

[0110] Understandably, in the ideal case of power equalization, the optical power in each waveguide is half of the input optical power. Therefore, with the same optical power density in a single waveguide, the density of the first optical signal coupled to EC 4111 can reach twice that of existing technologies (+3dB). Based on this, if this waveguide structure is applied to SOI silicon photonics chips, the probability of TPA effect in the waveguides of SOI silicon photonics chips can be effectively reduced, thereby effectively reducing the optical transmission loss caused by the TPA effect in the waveguides. For example, simulation tests show that, with other parameters unchanged, for the same target detection distance, the detection SNR can be improved by approximately 3dB, and for the same detection SNR, the target ranging capability can be improved by approximately 41%, effectively improving detection performance.

[0111] 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, resulting in a smaller volume and a reduction in the size of the chip containing the waveguide structure. It is also suitable for scenarios requiring the transmission of a single-mode optical signal, such as the transmitting component in an FMCW lidar. Furthermore, since only a single mode is transmitted in a single-mode waveguide, there is no interference from multiple modes or collisions between modes, thus improving the transmission efficiency of the optical signal.

[0112] Understandably, the two output terminals a of EC 4111 12 a 13Both also have a second mode size. EC 4111 can be understood as a component composed of multiple waveguide units, supporting a large input mode. This large mode is coupled towards the center of the two output modes under the action of the multiple waveguide units, gradually becoming two smaller modes. If the mode size of the two smaller modes is smaller than the second mode size, a transition section is needed to amplify the mode size of the two smaller modes. When the mode size of the two smaller modes is equal to the second mode size, this position is designated as the two outputs of EC 4111 and connected to the two waveguides 4112 and 4113. In this way, EC 4111 can transform a large input mode into two small output modes; therefore, EC 4111 can also be called a large mode coupler.

[0113] As an example, please refer to Figure 5a, which shows a possible structural schematic diagram of EC 4111. Figure 5a(A) shows a three-dimensional structural diagram of EC4111, and Figure 5a(B) shows a top view of EC4111. Combining Figures 5a(A) and (B), the EC 4111 includes two waveguide units, namely waveguide unit 1 and waveguide unit 2. Waveguide unit 1 and waveguide unit 2 are both arranged parallel to each other along the direction of light propagation (the horizontal direction in Figure 5a(B)). Their shape gradually changes from narrow to wide from left to right, with the middle gradually widening part serving as a transition section. The mode size of the widest part is the second mode size. If the two connected waveguides 4112 and 4113 are both single-mode waveguides, then it is equal to the mode size of the single-mode waveguide.

[0114] Figure 5b shows the optical power density diagram of the EC 4111 propagating optical signal in Figure 5a. Combining Figures 5a and 5b, the first optical signal S 11 The signal is input from the left end of waveguide unit 1 and waveguide unit 2, absorbed into the wide portion of waveguide unit 1 and waveguide unit 2, and coupled into the center of two small mode spots. Then, the mode spot size is increased through the transition section. When the transition reaches the second mode spot size, it is connected to the two waveguides 4112 and 4113.

[0115] It should be noted that the above description only presents one possible structure of EC 4111, and EC 4111 can also have other structures. Any coupler that can realize a large input pattern and two small output patterns can be used as EC 4111 in this application, and this application does not make any specific limitations on it.

[0116] Based on the above structure, a large-spot EC can be used to directly split the input optical signal into two waveguides, reducing the optical power in a single waveguide and making it less likely for high optical power density to occur in a single waveguide. When the waveguide is a waveguide in an SOI silicon photonics chip (referred to as an SOI waveguide), the SOI waveguide is also less prone to TPA effect, which can solve the problem caused by the TPA effect under high optical power density in SOI waveguides. In other words, with the same optical power density in the SOI waveguide as existing technologies, the SOI silicon photonics chip can support higher optical power input than existing technologies, increasing the maximum optical power that the SOI silicon photonics chip can withstand. In addition, the above structure adopts a completely passive waveguide structure, which can be directly formed by a single exposure without adding additional semiconductor process steps, or any additional processes and power consumption such as doping and power-up. It has the advantages of simple process, minimalist architecture, extremely low cost, extremely high performance, and extremely high reliability.

[0117] Optionally, in the waveguide structure shown in Figure 4, EC 4111, the first waveguide 4112, and the second waveguide 4113 are located in the transmitting component. The waveguide structure 400 may include one transmitting component or multiple transmitting components. The following describes in detail the schemes including one or more transmitting components through embodiments one through three.

[0118] Implementation Plan 1: Includes a launch component.

[0119] Please refer to Figure 6, which shows a schematic diagram of a waveguide structure provided in Implementation Scheme 1. In this example, in addition to 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 photonics chip. The chip includes at least two first transmitting ends and at least two second transmitting ends. The number of at least two first transmitting ends and at least two second transmitting ends can be the same or different, and is not limited. The first beam splitter 4114 is connected between the output end of the first waveguide 4112 and at least two first transmitting ends (b1 and b2 in the figure are examples) of the chip where the waveguide structure 400 is located. The second beam splitter 4115 is connected between the output end of the second waveguide 4113 and at least two second transmitting ends (b3 and b4 in the figure are examples) of the chip. The connection method can be a waveguide connection, an optical fiber connection, or any other connection that can realize optical signal transmission, and is not limited.

[0120] Based on the above structure and connection, the first beam splitter 4114 can split at least two first transmission signals from the input optical signal and output at least two first transmission signals through its at least two output terminals. The at least two first transmission signals are emitted to the scanning component through the at least two first transmission terminals of the chip and scanned to the detection space by the scanning component. Similarly, the second beam splitter 4115 can split at least two second transmission signals from the input optical signal and output at least two second transmission signals through its at least two output terminals. The at least two second transmission signals are also emitted to the scanning component through the at least two second transmission terminals of the chip and scanned to the detection space by the scanning component.

[0121] It should be noted that the number of at least two first transmission signals and the number of at least two second transmission signals can be the same or different. The figure shows an example with two of each, but it can also be two first transmission signals and three second transmission signals, or four first transmission signals and two second transmission signals, or three first transmission signals and three second transmission signals, etc., without limitation.

[0122] Optionally, at least two first transmission signals and at least two second transmission signals are used to measure the target. For example, taking the two first transmission signals and two second transmission signals in Figure 6 as an example, these four transmission signals can correspond to four detection channels. The four transmission signals are scanned into four regions by the subsequent scanning components. In this way, four regions can be detected in one scan, increasing the scanning range and improving detection efficiency. Each region can be a point, line, or surface, etc., without limitation.

[0123] Optionally, at least two of the first transmitted signals have the same optical power as at least two of the second transmitted signals. For example, in one example, both the first beam splitter 4114 and the second beam splitter 4115 are power beam splitters, and EC 4111 is based on the input first optical signal S. 11 Equal power distribution (e.g., for the first optical signal S) 11 The remaining optical signal after the local oscillator (LO) signal is separated is then divided into equal power signals to obtain the second optical signal S. 12 and the third optical signal S 13 The second optical signal S 12 The signal is input to the first beam splitter 4114, which splits it into at least two first transmitted signals with equal power, and the third optical signal S... 13The signal is input to the second beam splitter 4115, which splits it into at least two second transmitted signals with equal power. Based on this method, at least four transmitted signals will have the same optical power, and at least four transmitted signals can reach the same distance in the detection space, thereby obtaining detection results for different regions at the same distance. This detection method yields the best detection effect.

[0124] It should be noted that using the first and second beam splitters to split the transmitted signals into at least four signals for merging and detecting the target is only one possible implementation. Another implementation could be to directly combine the second optical signal S output by the EC 4111. 12 and the third optical signal S 13 In this scenario, where two transmitted signals are used to directly detect the target, the chip containing waveguide structure 400 can have only two transmitting ends, with the outputs of the first waveguide 4112 and the second waveguide 4113 directly connected to these two transmitting ends. Alternatively, in another implementation, one of the optical signals output by EC 4111 can be used as a single transmitted signal, while the other optical signal can be split into two transmitted signals by a beam splitter. These three transmitted signals can then be used to detect the target. Yet another implementation can use multiple beam splitters to generate four or more transmitted signals of any number to further increase the detection range. Many other possible implementations exist, which will not be listed here.

[0125] Optionally, as shown in Figure 6, the waveguide structure 400 may further include a receiving component 421, which is used to acquire the local oscillator signal S. 14 and echo signal S 15 And the local oscillator signal S 14 and echo signal S 15 Frequency mixing is performed to obtain an intermediate frequency (IF) signal, which is used to determine the target's velocity and / or distance. The receiving component 421 can receive the echo signal S from the receiving terminal c1 of the chip. 15 For example, one input terminal of the receiving component 421 can be connected to the receiving terminal c1 of the chip via a waveguide, optical fiber, or other means capable of transmitting optical signals. The transmitted signal is reflected by the target and becomes an echo signal S. 15 The signal is then transmitted back to the receiving end c1 of the chip, so that the receiving component 421 can receive the echo signal S from the receiving end c1. 15 .

[0126] In addition, the local oscillator signal S 14It can then be separated from the input signal, transmitted signal, or output signal of any of the devices in EC 4111, the first waveguide 4112, the second waveguide 4113, the first beamsplitter 4114, the second beamsplitter 4115, the waveguide after the first beamsplitter 4114, or the waveguide after the second beamsplitter 4115. For ease of understanding, three possible examples are given below.

[0127] Example 1, please refer to Figure 7a, which shows a possible structural diagram of the local oscillator signal being separated from the input signal of the EC 4111. In this structure, the EC 4111 also has a third output terminal a. 14 Another input of the receiving component 421 is connected to the third output a of EC 4111. 14 Up. EC 4111 received the first optical signal S. 11 Then, the first optical signal S 11 Coupled to three output terminals a 12 ~a 14 Above, where the first output terminal a 12 Output the second optical signal S 12 Second output terminal a 13 Output third optical signal S 13 Third output terminal a 14 Output local oscillator signal S 14 The receiving component 421 receives data from the third output terminal a. 14 Received local oscillator signal S 14 .

[0128] Optionally, the local oscillator signal S 14 The optical power is less than that of the second optical signal S 12 Optical power and third optical signal S 13 The optical power. For example, EC 4111 will transmit the first optical signal S 11 A relatively low-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 through power sharing. 12 Second output terminal a 13 Furthermore, the first beam splitter 4114 and the second beam splitter 4115 also perform power equalization processing, so that the at least four transmission signals emitted by the at least four transmitters of the chip will have equal power, and the light output of the at least four detection channels will be uniform.

[0129] Optionally, the receiving component 421 can be connected to the third output terminal a via a waveguide, optical fiber, or other means capable of transmitting optical signals. 14 Above. For example, Figure 7a shows a waveguide connection, in which case the third output of the EC 4111 can also have a second mode size; in other words, the three outputs of the EC 4111 are...12 ~a 14 They can all be connected to waveguides, such as to single-mode waveguides.

[0130] Example 2, please refer to Figure 7b, which shows a possible structural diagram of the local oscillator signal being split from the input signal of the second beamsplitter 4115. In this structure, assuming that the second beamsplitter 4115 splits into two second transmitted signals, the second beamsplitter 4115 also has a third output terminal, and another input terminal of the receiving component 421 is connected to the third output terminal of the second beamsplitter 4115. The second beamsplitter 4115 receives the third optical signal S. 13 Then, from the third optical signal S 13 The beam is split into two second transmission signals and a local oscillator signal S. 14 Local oscillator signal S 14 The signal is output through the third output terminal and enters the receiving component 421, while the two second transmission signals are transmitted to the two second transmission terminals b3 and b4 and emitted into the detection space.

[0131] Optionally, the local oscillator signal S 14 The optical power of the second beam splitter is less than the optical power of any of the second transmitted signals. For example, the second beam splitter 4115 receives the optical power of the third optical signal S. 13 The lower-power optical signal is split from the first beam splitter and output from its third output terminal, while the remaining higher-power optical signal is output from its first two output terminals through power splitting. In this case, the optical power of the two second transmitted signals is guaranteed to be the same. If EC 4111 and the first beam splitter 4114 also split the optical signals with equal power, then the optical power of the two first transmitted signals will be different from the optical power of the two second transmitted signals; specifically, it will be greater than the optical power of the two second transmitted signals.

[0132] Example 3, see Figures 7c and 7d, showing two possible structural diagrams for splitting the local oscillator signal from the signal transmitted in the second waveguide 4113. In this structure, the waveguide structure 400 also includes a beam splitter 413, which is coupled or connected between the second waveguide 4113 and another input terminal of the receiving assembly 421. The beam splitter 413 is used for the third optical signal S transmitted from the second waveguide 4113. 13 The split beam is the local oscillator signal S 14 and the local oscillator signal S 14 The output is sent to the receiving component 421. In this case, the optical power of the optical signal entering the second beam splitter 4115 is less than that of the second output terminal a of EC 4111. 22 The output third optical signal S 13 Optical power. Optionally, the local oscillator signal S 14 The optical power is less than the optical power of the optical signal entering the second beam splitter 4115. For example, the beam splitter 413 receives the optical signal S from the third optical signal S.13 The lower-power optical signal is split off and output to the receiving component 421, while the remaining high-power optical signal is output to the second beam splitter 4115.

[0133] The beam splitter 413 can be a directional coupler, as shown in Figure 7c. This directional coupler does not contact the second waveguide 4113, but is relatively close to it. In other words, a directional coupler can be placed sufficiently close to the second waveguide 4113, allowing the directional coupler to transmit the third optical signal S from the second waveguide 4113. 13 The local oscillator signal S is split into two signals with unequal power. 14 Alternatively, the beam splitter 413 can also be a beam splitter, as shown in Figure 7d. This beam splitter is directly inserted in the middle of the second waveguide 4113, splitting the third optical signal S transmitted in the second waveguide 4113. 13 The spectral dispersion is the local oscillator signal S. 41 And to measure optical signals.

[0134] Understandably, the three examples above are only for illustrating how to extract the local oscillator signal S from the input signal. 14 Several possible structures are given, and other branched structures can be deduced by analogy with the above structures, which will not be repeated here.

[0135] Optionally, the receiving component 421 can be any component or combination thereof capable of performing mixing. For example, taking the structure shown in Figure 7c as an example, please refer to Figure 8, which shows a specific structural schematic diagram of a receiving component provided in Embodiment 1. Combining Figures 7c and 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, as shown in Figure 8, the receiving component 421 can include a fourth beam splitter 4211 and four mixers, namely mixers 42121, 42122, 42123, and 42124. The input terminal of the fourth beam splitter 4211 is the input terminal of the receiving component 421, used to acquire the local oscillator signal S. 14 The four outputs of the fourth beam splitter 4211 are connected to the four first inputs of the four mixers 42121 to 42124, respectively. The four second inputs of the four mixers 42121 to 42124 are connected to the four receivers of the chip. 11 c 12 c 13 and c 14 Here, the connections between the various components can be achieved through waveguides, optical fibers, or other means that can transmit optical signals. Figure 8 shows a waveguide connection as an example.

[0136] Based on this structure and connection, the input of the fourth beam splitter 4211 can receive the local oscillator signal S. 14The fourth beam splitter 4211 splits the local oscillator signal S 14 Spectroscopy (e.g., equal power splitting) is divided into four sub-local oscillator signals S. 141 S 142 S 143 S 144 And through its four output terminals, these four sub-local oscillator signals S 141 ~S 144 The outputs are respectively sent to four mixers 42121 to 42124. The four mixers 42121 to 42124 can also receive signals from the chip's four receiver terminals c. 11 ~c 14 Four echo signals S were received 151 S 152 S 153 S 154 Each mixer performs a mixing operation on the received sub-local oscillator signal and echo signal to generate its own intermediate frequency signal. The four intermediate frequency signals generated by the four mixers 42121 to 42124 are combined to determine the target's distance and / or velocity; in other words, they work together to achieve target measurement.

[0137] Optionally, the four mixers 42121-42124, together with subsequent components, can be used to achieve target measurement. For example, as shown in Figures 7c and 8, the receiving component 421 may also include a detection element 4213. The detection element 4213 is connected between the output terminals of the four mixers 42121-42124 and the electrical output terminal d of the chip. It 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. This electrical signal is transmitted to subsequent components, such as an electrical chip, through the electrical output terminal d of the chip. In the electrical chip, the intermediate frequency signal is processed to obtain point cloud data and determine the distance and / or velocity of the target. See the description of the detection device below for related details; further explanation is not provided here.

[0138] Optionally, one transmitting component is used to transmit an optical signal of one wavelength. In embodiment one, since the waveguide structure 400 includes one transmitting component, the four transmitted signals have the same wavelength, and the four sub-local oscillator signals S 141 ~S 144 The wavelengths 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, while signals of other wavelengths are discarded. Therefore, the four intermediate frequency signals are all signals of the same wavelength, and this wavelength is the same as the wavelength of the transmitted signal. Based on these four intermediate frequency signals to measure the target, the measurement accuracy can be improved.

[0139] 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 correlation 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.

[0140] Implementation Plan 2: Includes two launch components.

[0141] Please refer to Figure 9, which shows a schematic diagram of a waveguide structure provided in Embodiment 2. 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. For example, as shown in Figure 9, one transmitting component includes EC 4111, the first waveguide 4112, and the second waveguide 4113, while the other transmitting component includes EC 4121, the first waveguide 4122, and the second waveguide 4123. In this scenario, the waveguide structure 400 further includes a first beam combiner / splitter 431 and a second beam combiner / splitter 432. Taking an example where the chip containing the waveguide structure 400 includes two first transmitting terminals b1 and b2 and two second transmitting terminals b3 and b4, the first beam combiner / splitter 431 and the second beam splitter 432 each have two input terminals and two output terminals. The two input terminals of the first beam combiner / splitter 431 are respectively connected to the output terminals of the two first waveguides 4112 and 4122 in the two transmitting components, and the output terminal of the first beam combiner / splitter 431 is connected to the two first transmitting terminals b1 and b2 of the chip. The two input terminals of the second beam combiner / splitter 432 are respectively connected to the output terminals of the two second waveguides 4113 and 4123 in the two transmitting components, and the output terminal of the second beam combiner / splitter 432 is connected to the two second transmitting terminals b3 and b4 of the chip.

[0142] Based on this structure and connection, in the transmitting component above, EC 4111 receives the first input optical signal S. 11 The second optical signal S is output from the split beam. 12 and the third optical signal S 13 The second optical signal S 12 The third optical signal S is transmitted through the first waveguide 4112 to the first beam combiner / splitter 431. 13 The signal is transmitted through the second waveguide 4113 to the second beam combiner / splitter 432. In the lower transmitting assembly, EC 4121 receives the first optical signal S from the input. 21 The second optical signal S is output from the split beam. 22 and the third optical signal S 23 The second optical signal S 22 The third optical signal S is transmitted through the first waveguide 4122 to the first beam combiner / splitter 431. 23The light is transmitted through the second waveguide 4123 to the second beam combiner / splitter 432. The first beam combiner / splitter 431 splits the two input optical signals into two first transmitted signals and outputs these two first transmitted signals through its two output terminals, so that the two first transmitted signals are transmitted to the two first transmitting terminals b1 and b2 of the chip, and then emitted to the scanning component. The second beam combiner / splitter 432 splits the two input optical signals into two second transmitted signals and outputs these two second transmitted signals through its two output terminals, so that the two second transmitted signals are transmitted to the two second transmitting terminals b3 and b4 of the chip, and also emitted to the scanning component.

[0143] Optionally, the two first transmitted signals and the two second transmitted signals are scanned into the detection space by the scanning component to measure the target in the detection space. For example, the two first transmitted signals and the two second transmitted signals correspond to four detection channels. More specifically, the two first transmitted signals and the two second transmitted signals are scanned into four regions by the subsequent scanning component. In this way, four regions can be detected in one scan, increasing the scanning range and improving detection efficiency.

[0144] Optionally, the two first transmitted signals and the two second transmitted signals have the same optical power. For example, in one example, the first beam combiner / splitter 431 and the second beam combiner / splitter 432 are both power beam splitters. EC 4111 and EC 4121 both obtain second and third optical signals by equally splitting the input first optical signal (for example, equally splitting the remaining optical signal after the local oscillator signal is separated from the first optical signal). The two second optical signals are input to the first beam combiner / splitter 431, and after being combined by the first beam combiner / splitter 431, they are equally split into two first transmitted signals. The two third optical signals are input to the second beam combiner / splitter 432, and after being combined by the second beam combiner / splitter 432, they are equally split into two second transmitted signals. Based on this method, these four transmitted signals will have the same optical power, and these four transmitted signals can reach the same distance in the detection space, thereby obtaining detection results for different regions at the same distance. The detection effect is the best under this detection method.

[0145] In one example, two first optical signals S from two transmitting components 11 S 21 They have different wavelengths. In other words, the first optical signal S 11 Having a first wavelength, a first optical signal S 21 It 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 from the split beam 12 S 22 They also have different wavelengths, two third optical signals S 13 S23 They also have different wavelengths. Therefore, the first beam combiner / splitter 431 and the second beam combiner / splitter 432 will receive two input signals of different wavelengths. Each beam combiner / splitter combines the two input signals of different wavelengths and splits them into two dual-wavelength transmission signals and outputs 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.

[0146] Or, in another example, two first optical signals S in two transmitting components 11 S 21 They have the same wavelength but different linear polarization states; in other words, the two first optical signals S... 11 S 21 These are light rays in different linearly polarized states. For example, the first optical signal S... 11 For TE light, the first optical signal S 21 For TM light, or the first optical signal S 11 For TM light, the first optical signal S 21 For TE light, or the first optical signal S 11 The first optical signal S is for P-light. 21 For S-light, or the first optical signal S 11 The first optical signal S for S-light 21 For P-beams, the waveguide structure 400 also needs to incorporate polarization elements, such as a polarization beam splitter (PBS) or a polarization beam splitter rotator (PSR). These polarization elements, based on different linear polarization states, split the echo signals corresponding to different transmitting components, thereby mixing the echo signals corresponding to each transmitting component.

[0147] Or, in another example, the two first optical signals S in the two transmitting components 11 S 21 They have the same wavelength and the same linear polarization state, but the waveguide structure 400 is equipped with polarization elements. The polarization elements are used to polarize and split the echo signal, thereby separating the echo signals corresponding to different transmitting components, so as to mix the echo signals corresponding to each transmitting component.

[0148] It should be noted that the implementation methods of the echo signals corresponding to different transmitting components of the polarization element beam splitting can be found in existing solutions, and will not be described in detail here.

[0149] Alternatively, in the example of Figure 9, four dual-wavelength transmitted signals are generated by a beam combiner / splitter to combine and detect the target; this is just one possible implementation. In another implementation, the two second optical signals S output by the EC 4111 can also be directly combined. 12 and the third optical signal S 13 And the two second optical signals S output by EC 4121 22 and the third optical signal S 23 To directly detect a target using four transmitted signals, the chip still has four transmitting ends. The outputs of the first waveguides 4112 and 4122, and the second waveguides 4113 and 4123 are directly connected to these four transmitting ends. However, the four transmitted signals emitted by these four transmitting ends are all single-wavelength signals, with two signals of one wavelength and the other two of another wavelength. Alternatively, in another implementation, one of the optical signals output from EC 4111 and one of the optical signals output from EC 4121 can be directly used as two single-wavelength transmitted signals. The other optical signals output from EC 4111 and EC 4121 can be split into two dual-wavelength transmitted signals using a beam combiner / splitter. These four transmitted signals are then used to detect the target. Another implementation can further use more beam splitters or beam combiners / splitters to split the signal into four or more transmitted signals to further increase the detection range. There are many other possible implementations, which will not be listed here.

[0150] Optionally, as shown in Figure 9, the waveguide structure 400 may further include a receiving component. This receiving component acquires the local oscillator signal and the echo signal, and mixes them to obtain an intermediate frequency (IF) signal. This IF signal is used to determine the target's velocity and / or distance. The receiving component can receive the echo signal from the chip's receiving end c. For example, one input terminal of the receiving component can be connected to the chip's receiving end c via a waveguide, optical fiber, or other means capable of transmitting optical signals. The transmitted signal is reflected by the target and becomes an echo signal, returning to the chip's receiving end c, allowing the receiving component to receive the echo signal from that receiving end c.

[0151] Additionally, there may be one or more receiving components, and the local oscillator signal of each receiving component can be derived from the input signal, transmitted signal, or output signal of any of the following devices: EC (i.e., EC 4111 and EC 4121), first waveguide (i.e., first waveguide 4112 and first waveguide 4122), second waveguide (i.e., second waveguide 4113 and second waveguide 4123), first beam combiner / splitter 431, second beam combiner / splitter 432, waveguide after first beam combiner / splitter 431, or waveguide after second beam combiner / splitter 432. For ease of understanding, four possible examples are given below.

[0152] Example 1, please refer to Figure 10a, which shows a possible structural diagram of the local oscillator signal being separated from the signal transmitted by the second beam combiner / splitter 432. In this structure, there is only one receiving component, called receiving component 421. The second beam combiner / splitter 432 also has a third output terminal. One input terminal of 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 Then, first send the two third optical signals S 13 S 23 The beam is combined into one beam and then split into two second transmission signals and a local oscillator signal S4. The local oscillator signal S4 is output through the third output terminal and enters the receiving component 421, while the two second transmission signals are transmitted to the two transmitting terminals b3 and b4 and emitted into the detection space.

[0153] Optionally, in the two third optical signals S 13 S 23 When the wavelengths are different, the two third optical signals S 13 S 23 The two wavelengths of the optical signal are combined into a single dual-wavelength optical signal. Therefore, the local oscillator signal S4, which is split from this dual-wavelength optical signal, is also dual-wavelength. The receiving component 421 can mix the signals of these two wavelengths in the echo signal with the signals of these two wavelengths in the local oscillator signal S4 based on these two wavelengths to directly obtain the intermediate frequency signals of these two wavelengths, while the signals of other wavelengths in the echo signal are directly filtered out as noise signals.

[0154] Optionally, the optical power of the local oscillator signal S4 is less than the optical power of any of the second transmitted signals. For example, the second beam combiner / splitter 432 receives the optical power from the third optical signal S4. 13 The lower-power optical signal is split from the first output and output from its third output terminal, while the remaining higher-power optical signal is output from its first two output terminals through power equalization. In this case, the optical power of the two second transmitted signals is guaranteed to be the same. If EC 4111, EC 4121, and the second beam combiner / splitter 432 also split the optical signals with equal power, then the optical power of the two first transmitted signals will be different from the optical power of the two second transmitted signals; specifically, it will be greater than the optical power of the two second transmitted signals.

[0155] Example 2, please refer to Figure 10b, which shows a possible structural diagram of the local oscillator signal being separated from the input signals of EC 4111 and EC 4121. In this structure, there are two receiving components, referred to as 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.

[0156] For the receiving component 421, EC 4111 also has a third output terminal a 14 One input terminal of the receiving component 421 is connected to the receiving terminal c1 of the chip, and the other input terminal is connected to the third output terminal a of EC 4111. 14 Up. EC 4111 received the first optical signal S. 11 Then, the first optical signal S 11 Coupled to its three output terminals a 12 a 13 a 14 Above, where the first output terminal a 12 Output the second optical signal S 12 Second output terminal a 13 Output third optical signal S 13 Third output terminal a 14 Output local oscillator signal S 14 Assume the first optical signal S 11 If it has a first wavelength, then the local oscillator signal S 14 It also has a first wavelength, and the receiving component 421 receives the signal from the third output terminal a of EC 4111. 14 Received local oscillator signal S of the first wavelength 14 And receive the echo signal S from the receiver C1 of the chip. 15 Using echo signal S 15 The signal of the first wavelength and the local oscillator signal S 14 The frequency is mixed to obtain the intermediate frequency signal of the first wavelength.

[0157] Similarly, for receiver component 422, EC 4121 also has a third output terminal a 24 One input terminal of the receiving component 422 is connected to the receiving terminal c2 of the chip, and the other input terminal is connected to the third output terminal a of EC 4121. 24 Up. EC 4121 received the first optical signal S. 21 Then, the first optical signal S 21 Coupled to its three output terminals a 22 a 23 a 24 Above, where the first output terminal a 22 Output the second optical signal S 22 Second output terminal a 23 Output third optical signal S 23 Third output terminal a 24 Output local oscillator signal S 24 Assume the second optical signal S 21 If it has a second wavelength, then the local oscillator signal S 24It also has a second wavelength, and the receiving component 422 is located at the third output terminal a of EC 4121. 24 Received local oscillator signal S of the second wavelength 24 And receive the echo signal S from the receiver C2 of the chip. 25 Using echo signal S 25 The signal of the second wavelength and the local oscillator signal S 24 The frequency is mixed to obtain the intermediate frequency signal of the second wavelength.

[0158] Understandably, the local oscillator signal is single-wavelength, but the four transmitted signals are dual-wavelength. Therefore, each echo signal also has at least two wavelengths. When each echo signal performs a mixing operation in its corresponding receiving component, it is only mixed with a single wavelength of the current local oscillator signal, while signals of other wavelengths are discarded to improve the quality of the intermediate frequency signal.

[0159] Optionally, for each EC, the optical power of its divided local oscillator signal is less than the optical power of the divided second optical signal and the optical power of the divided third optical signal. For example, EC 4111 divides the first optical signal S... 11 A relatively low-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 through power sharing. 12 Second output terminal a 13 Up. EC 4121 will send the first optical signal S 21 A similarly 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 through power sharing. 22 Second output terminal a 23 Furthermore, the first beam combiner / splitter 431 and the second beam combiner / splitter 432 also perform power equalization processing, so that the four transmission signals emitted by the four transmitters of the chip will have equal power, and the light output of the four detection channels will be uniform.

[0160] Example 3, please refer to Figure 10c, which shows a possible structural diagram of the local oscillator signal being separated from the signals transmitted by the first waveguide 4112 and the second waveguide 4123. In this structure, there are also two receiving components, referred to as 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.

[0161] For the receiving component 421, the waveguide structure 400 further includes a directional coupler 4311. The directional coupler 4311 is coupled between the first waveguide 4112 and one input terminal of the receiving component 421, and the other input terminal of the receiving component 421 is connected to the receiving terminal c1 of the chip. The directional coupler 4311 does not contact the first waveguide 4112, but is relatively close to it; therefore, it can transmit the second optical signal S from the first waveguide 4112. 12 The local oscillator signal S is coupled out from the middle. 14 and the local oscillator signal S 14 Output to receiving component 421. Assume the first optical signal S... 11 Having a first wavelength, the second optical signal S 12 It also has a first wavelength, and the receiving component 421 receives the second optical signal S through the directional coupler 4311. 12 The local oscillator signal S of the first wavelength is coupled out from the middle. 14 And receive the echo signal S from the receiver C1 of the chip. 15 Using echo signal S 15 The signal of the first wavelength and the local oscillator signal S 14 The frequency is mixed to obtain the intermediate frequency signal of the first wavelength.

[0162] Similarly, for the receiving component 422, the waveguide structure 400 also includes a directional coupler 4312. The directional coupler 4312 is coupled between the second waveguide 4123 and one input terminal of the receiving component 422, and the other input terminal of the receiving component 422 is connected to the receiving terminal c2 of the chip. The directional coupler 4312 does not contact the second waveguide 4123, but is relatively close to it; therefore, it can transmit the third optical signal S from the second waveguide 4123. 23 The local oscillator signal S is coupled out from the middle. 24 and the local oscillator signal S 24 Output to receiving component 422. Assume the first optical signal S... 21 If it has a second wavelength, then the third optical signal S 23 It also has a second wavelength, and the receiving component 422 receives the third optical signal S through the directional coupler 4312. 23 The second wavelength local oscillator signal S is coupled out from the middle. 24 And receive the echo signal S from the receiver C2 of the chip. 25 Using echo signal S 25 The signal of the second wavelength and the local oscillator signal S 24 The frequency is mixed to obtain the intermediate frequency signal of the second wavelength.

[0163] Based on the above beam splitting method, the optical power of the optical signal entering the beam combiner / splitter will be less than the optical power of the optical signal output from the EC to the split waveguide. For example, the optical power of the optical signal entering the first beam combiner / splitter 431 is less than the second optical signal S output from the EC 4111 to the first waveguide 4112. 12 The optical power of the optical signal entering the second beam combiner / splitter 432 is less than the optical power of the third optical signal S output from EC 4121 to the second waveguide 4123. 23 The optical power.

[0164] Optionally, the optical power of the local oscillator signal split from the beam-splitter is less than the optical power of the optical signal entering the subsequent beam combiner / splitter. For example, the directional coupler 4311 receives the second optical signal S... 12 The lower-power optical signal is split from the first beam combiner / splitter 431 and output to the receiving component 421, while the remaining high-power optical signal is output to the first beam combiner / splitter 431. The directional coupler 4312 receives the third optical signal S... 23 A lower-power optical signal is split off and output to the receiving component 422, while the remaining high-power optical signal is output to the second beam combiner / splitter 432. In this way, the higher-power beam can be used as the transmitted signal to improve the target detection effect.

[0165] Understandably, the directional coupler described above is a type of beam-splitting element. This directional coupler can also be replaced with other elements capable of beam splitting, such as a beam splitter. Taking a beam splitter as an example, the beam splitting method can also include the following example four:

[0166] Example 4, as shown in Figure 10d, illustrates another possible structural diagram for separating the local oscillator signal from the signals transmitted in the first waveguide 4112 and the second waveguide 4123. This structure differs from that in Example 3 in that the directional coupler 4311 in Example 3 is replaced by the beam splitter 433 in Example 4, and the directional coupler 4312 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 then connected to subsequent components via the waveguide.

[0167] For example, as shown in Figure 10d, the input terminal of beam splitter 433 is connected to the output terminal of first waveguide 4112, and the two output terminals are respectively connected to one input terminal of first beam combiner / splitter 431 and one input terminal of receiving component 421. Beam splitter 433 splits the second optical signal S output from first waveguide 4112. 12 The spectral splitting consists of the measurement optical signal and the local oscillator signal S. 14 The measurement optical signal is output to the first beam combiner / splitter 431 to participate in the target measurement, and the local oscillator signal S is output to the first beam combiner / splitter 431.14 The output is sent to the receiving component 421 to complete the connection with the echo signal S. 15 The mixing is performed. Similarly, the input of beam splitter 434 is connected to the output of second waveguide 4123, and the two outputs are respectively connected to one input of second beam combiner / splitter 432 and one input of receiving component 422. Beam splitter 434 mixes the third optical signal S output from second waveguide 4123. 23 The spectral splitting consists of the measurement optical signal and the local oscillator signal S. 24 The measurement optical signal is output to the second beam combiner / splitter 432 to participate in the target measurement, and the local oscillator signal S is output to the second beam combiner / splitter 432. 24 Output to receiver 422 to complete the connection with echo signal S 25 Frequency mixing.

[0168] Understandably, the four examples above are just a few possible structures for extracting the local oscillator signal from the input signal. Other extraction structures can be deduced by analogy with the above structures, and will not be repeated here.

[0169] Optionally, the above receiving component can be any component or combination thereof capable of performing mixing. For example, taking the structure shown in Figure 10a as an example, please refer to Figure 11a, which shows a specific structural schematic diagram of a receiving component provided in Embodiment 2. Combining Figures 10a and 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 used as an example. The K mixers are mixers 42121, 42122, 42123, and 42124. The input terminal of the fourth beam splitter 4211 is the input terminal of the receiving component 421, used to acquire the local oscillator signal S4. The four output terminals of the fourth beam splitter 4211 are respectively connected to the four first input terminals of the four mixers 42121 to 42124, and the four second input terminals of the four mixers 42121 to 42124 are connected to the four receiving terminals c1, c2, c3, and c4 of the chip. Here, the connection between the various components can be achieved through waveguides, optical fibers, or other means that can transmit optical signals. Figure 11a shows a waveguide connection as an example.

[0170] Based on this structure and connection, the input of the fourth beam splitter 4211 can receive the dual-wavelength local oscillator signal S4. The fourth beam splitter 4211 splits the dual-wavelength local oscillator signal S4 (e.g., equally distributed with equal power) into four dual-wavelength sub-local oscillator signals S1 and S2. 41 S 42 S 43 S 44 And through its four output terminals, these four dual-wavelength sub-local oscillator signals S 41 ~S 44The signals are output to four mixers 42121 to 42124 respectively. The four mixers 42121 to 42124 can also receive four echo signals S from the four receivers c1 to c4 of the chip. 51 S 52 S 53 S 54 Each mixer performs a mixing operation on the signal in the received echo signal that has the same wavelength as the dual-wavelength sub-local oscillator signal, generating its own intermediate frequency (IF) signal. The four IF signals generated by the four mixers 42121 to 42124 together achieve the target measurement.

[0171] Optionally, the four mixers 42121-42124, together with subsequent components, can be used to achieve target measurement. For example, as shown in Figures 10a and 11a, the receiving component 421 may also include a detection element 4213. The detection element 4213 is connected between the output terminals of the four mixers 42121-42124 and the electrical output terminal d of the chip. It 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. This electrical signal is transmitted to subsequent components, such as an electrical chip, through the electrical output terminal d of the chip. In the electrical chip, the intermediate frequency signal is processed to obtain point cloud data and determine the distance and / or velocity of the target.

[0172] The structure of the receiving component 421 shown in Figure 11a can be directly deduced from the receiving component 422. For example, referring to Figure 11b, and combining Figure 11a and Figure 10c above, and still taking K=4 as an example, the receiving component 421 includes a fourth beam splitter 4211 and four mixers 42121 to 42124. The input terminal of the fourth beam splitter 4211 is the input terminal of the receiving component 421, used to acquire the local oscillator signal S. 14 The four outputs of the fourth beam splitter 4211 are respectively connected to the four first inputs of the four mixers 42121 to 42124, and the four second inputs of the four mixers 42121 to 42124 are connected to the four receiving terminals c 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 mixers 42221, 42222, 42223, and 42224. The input terminal of the fourth beam splitter 4221 is the input terminal of the receiving component 422, used to acquire the local oscillator signal S. 24 The four outputs of the fourth beam splitter 4221 are respectively connected to the four first inputs of the four mixers 42221 to 42224, and the four second inputs of the four mixers 42221 to 42224 are connected to the other four receiving terminals of the chip. 21 c 22 c23 and c 24 .

[0173] Based on this structure and connection relationship, assuming the first optical signal S 11 If the wavelength is the first wavelength, then in the receiving component 421, the input terminal of the fourth beam splitter 4211 can receive the local oscillator signal S of the first wavelength. 14 The fourth beam splitter 4211 splits the local oscillator signal S of the first wavelength. 14 Spectroscopy (e.g., equal power splitting) is divided into four sub-local oscillator signals S with the first wavelength. 141 S 142 S 143 S 144 And through its four output terminals, these four first-wavelength sub-local oscillator signals S 141 ~S 144 The outputs are respectively sent to four mixers 42121 to 42124. The four mixers 42121 to 42124 can also receive signals from the chip's four receiver terminals c. 11 ~c 14 Four echo signals S were received 151 S 152 S 153 S 154 Each mixer performs a mixing operation on the first wavelength signal in the received echo signal and the sub-local oscillator signal to generate its own intermediate frequency (IF) signal. The four IF signals generated by the four mixers 42121 to 42124 are all IF signals of the first wavelength. In other words, they can indicate relevant information about the target at the measurement distance corresponding to the first wavelength, such as distance and / or velocity.

[0174] Similarly, suppose the first optical signal S 21 If the wavelength is the second wavelength, then in the receiving component 422, the input terminal of the fourth beam splitter 4221 can receive the local oscillator signal S of the second wavelength. 24 The fourth beam splitter 4221 splits the second wavelength local oscillator signal S 24 The light is split (e.g., evenly divided with equal power) into four sub-local oscillator signals S with a second wavelength. 241 S 242 S 243 S 244 And through its four output terminals, these four second-wavelength sub-local oscillator signals S 241 ~S 244 The outputs are distributed to four mixers 42221 to 42224. The four mixers 42221 to 42224 can also receive signals from four other receivers on the chip. 21 ~c 24 Four echo signals S were received 251 S 252 S 253S 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 (IF) signal. The four IF signals generated by the four mixers 42221 to 42224 are all second wavelength IF signals. In other words, they can indicate relevant information about the target at the measurement distance corresponding to the second wavelength, such as distance and / or velocity.

[0175] Optionally, the eight mixers 42121–42124 and 42221–42224 can be combined with subsequent components to achieve target measurement. For example, as shown in Figure 11b, the waveguide structure may also include a detection element 423. The detection element 423 is connected between the output terminals of the eight mixers 42121–42124 and 42221–42224 and the electrical output terminal d of the chip. It is used to perform photoelectric detection on the eight intermediate frequency signals generated by the eight mixers 42121–42124 and 42221–42224, obtain electrical signals, and output them. The electrical signals are transmitted to subsequent components, such as an electrical chip, through the electrical output terminal d of the chip. In the electrical chip, the intermediate frequency signals are processed to obtain point cloud data and determine the distance and / or velocity of the target.

[0176] 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 one of the receiving components can be separated from the correlation 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.

[0177] Implementation Plan 3: Includes N launching components.

[0178] Please refer to Figure 12, which shows a schematic diagram of a waveguide structure provided in Implementation Scheme 3. In this example, the waveguide structure 400 includes N transmitting components, where N is an integer greater than or equal to 2. It is understood that Implementation Scheme 2 above is a special case of Implementation Scheme 3, specifically the structure when N = 2 in Implementation Scheme 3.

[0179] As shown in Figure 12, each of the N transmitting components includes the EC, first waveguide, and second waveguide described above. For example, as shown in Figure 12, from top to bottom, the first transmitting component includes EC 4111, first waveguide 4112, and second waveguide 4113; the second transmitting component includes EC 4121, first waveguide 4122, and second waveguide 4123; ..., the Nth transmitting module includes EC 41N1, first waveguide 41N2, and second waveguide 41N3. In this case, the waveguide structure 400 also includes a first beam combiner / splitter 431 and a second beam combiner / splitter 432. Both the first beam combiner / splitter 431 and the second beam splitter 432 have N input terminals and at least two output terminals. The figure shows two output terminals as an example. The N input terminals of the first beam combiner / splitter 431 are respectively connected to the output terminals of the N first waveguides 4112 to 41N2 in the N transmitting components, and the two output terminals of the first beam combiner / splitter 431 are connected to the two first transmitting terminals b1 and b2 of the chip. The N input terminals of the second beam combiner / splitter 432 are respectively connected to the output terminals of the N second waveguides 4113 to 41N3 in the N transmitting components, and the two output terminals of the second beam combiner / splitter 432 are connected to the two second transmitting terminals b3 and b4 of the chip.

[0180] Optionally, the N first optical signals S received by the N transmitting modules 11 ~S N1 These are different wavelengths. In each transmitting component, the EC splits the input single-wavelength first optical signal into single-wavelength second and third optical signals. The single-wavelength second optical signal is transmitted through the first waveguide to the first beam combiner / splitter 431, and the single-wavelength third optical signal is transmitted through the second waveguide to the second beam combiner / splitter 432. The first beam combiner / splitter 431 combines the input N wavelengths of the second optical signal S... 12 ~S N2 After being combined into a single beam, the light is then split into two first emission signals, both of which are N-wavelength optical signals. These two N-wavelength first emission signals are emitted from the two first emission terminals b1 and b2 of the chip, respectively, and then sent to the scanning component. Similarly, the second beam combiner / splitter 432 combines the input N-wavelength third optical signals S... 13 ~S N3 After being combined into a single beam, the light is then split into two second emission signals, which are also N-wavelength optical signals. These two N-wavelength second emission signals are emitted from the two second emission terminals b3 and b4 of the chip and sent to the scanning assembly. The two first emission signals and the two second emission signals are scanned into the detection space by the scanning assembly and used to jointly measure the target in the detection space.

[0181] Alternatively, the N first optical signals S received by the N transmitting modules 11 ~S N1It could also be the same wavelength but with different linear polarization states, or the same wavelength and the same linear polarization state, but using different polarization elements to distinguish their respective echo signals, or some of the first optical signals are different wavelengths, while other first optical signals are the same wavelength but with different linear polarization states, or some of the first optical signals are the same wavelength but with different linear polarization states, while other first optical signals have the same wavelength and the same linear polarization state but are distinguished by polarization elements, and so on. There are many possible implementation methods, and no specific limitation is made here.

[0182] Optionally, similar to embodiment two above, the waveguide structure 400 may further include one or more receiving components. The local oscillator signal of each receiving component can be separated from the input signal, transmitted signal, or output signal of one element among N ECs 4111–41N1, N first waveguides 4112–41N2, N second waveguides 4113–41N3, the first beam combiner / splitter 431, the second beam combiner / splitter 432, the waveguide after the first beam combiner / splitter 431, and the waveguide after the second beam combiner / splitter 432. For example:

[0183] In one example, Figure 13a shows a structural diagram of a waveguide structure 400 including a receiving component. This diagram illustrates the example of the local oscillator signal S4 being separated from the signal transmitted by the second beam combiner / splitter 432. The scheme for separating the signal from the first beam combiner / splitter 431 can be deduced by analogy to this diagram. In this example, the second beam combiner / splitter 432 also has a third output terminal connected to the receiving module 421. The second beam combiner / splitter 432 can also separate an N-wavelength local oscillator signal S4 from a synthesized N-wavelength beam signal. This N-wavelength local oscillator signal S4 enters the receiving module 421 and is mixed with the echo signal received by the chip's receiving terminal c across N wavelengths to obtain an intermediate frequency signal.

[0184] In another example, Figure 13b shows a structural diagram of waveguide structure 400 including N receiving components, with N local oscillator signals S 14 S 24 ... S N4Taking the input signals from EC4111, EC4121, ..., EC41N1 as an example. In this example, the N receiving components are receiving component 421, receiving component 422, ..., receiving component 42N. The N receiving components 421 to 42N correspond one-to-one with the N ECs 4111 to EC 41N1. Each of the N ECs 4111 to 41N1 also has a third output terminal, which is connected to the corresponding receiving component. Each EC can also extract a single-wavelength local oscillator signal from the input single-wavelength first optical signal and transmit it to the connected receiving module. This single-wavelength local oscillator signal is mixed with the received echo signal at a single wavelength in the receiving component to obtain the intermediate frequency signal. When the first optical signal S input to the N ECs 4111 to 41N1... 11 ~S N1 When there are N wavelengths, there are N local oscillator signals S 14 ~S N4 It also has N wavelengths, each local oscillator signal is a single wavelength, and each receiving component only mixes the signal with the same wavelength as the local oscillator signal in the echo signal it receives, and signals of other wavelengths can be discarded;

[0185] In another example, Figure 13c shows a different structural diagram of waveguide structure 400 including N receiving components 421-42N, with N local oscillator signals S 14 S 24 ... S N4 Taking the separation of signals transmitted from any of the waveguides following EC 4111 to EC 41N1 as an example, the waveguide structure 400 also includes N beam splitting elements. The illustration shows N directional couplers 4311, 4312, ..., 431N as an example. These N directional couplers 4311 to 431N correspond one-to-one with N receiving components 421 to 42N. Each directional coupler can be coupled between the first waveguide of any transmitting component and the input terminal of the corresponding receiving component, or between the second waveguide of any transmitting component and the input terminal of the corresponding receiving component. Each directional coupler is used to separate a single-wavelength local oscillator signal from the single-wavelength optical signal transmitted in the coupled first or second waveguide, and outputs the single-wavelength local oscillator signal to the coupled receiving component. This single-wavelength local oscillator signal is mixed with the received echo signal in the receiving component at a single wavelength to obtain an intermediate frequency (IF) signal. When the first optical signal S input to the N EC 4111 to 41N1... 11 ~S N1 With N wavelengths, N receiving components can mix to obtain the intermediate frequency signals corresponding to each of the N wavelengths.

[0186] Based on the above implementation scheme three, N transmitting components and one or N receiving components can be set in the waveguide structure. When only one receiving component is set, its local oscillator signal 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 correlation signal of one transmitting component, and the local oscillator signals of the N receiving components are all single-wavelength signals with different wavelengths. This waveguide structure has high flexibility and versatility and can be adapted to various detection applications.

[0187] It is understandable that, unless otherwise specified or logically conflicting, the terminology and / or descriptions of the various implementation schemes described above are consistent and can be referenced from each other. The technical features of different implementation schemes can be combined to form new implementation schemes based on their inherent logical relationships.

[0188] Furthermore, the above implementation schemes can be modified to form new implementation schemes. For example, in another example, in implementation scheme three above, more than N receiving components can be set. For instance, a local oscillator signal can be separated from each first waveguide and each second waveguide, resulting in 2N local oscillator signals, corresponding to 2N receiving components. Alternatively, local oscillator signals can be separated from some of the first and second waveguides connected to the same EC, forming any number of local oscillator signals more than N but less than 2N, and the same number of receiving components can be set. Alternatively, other beam splitting elements besides directional couplers and beam splitters can be used to achieve the effect of separating local oscillator signals. And so on, which will not be listed here.

[0189] The waveguide structures described above can be applied to chips, such as silicon photonic chips, specifically SOI silicon photonic chips.

[0190] Please refer to Figure 14, which shows a possible structural schematic diagram of a silicon photonic chip provided in this application. The silicon photonic chip 1400 includes a waveguide structure, which can be any waveguide structure described above, such as the waveguide structure 400 in any of the figures above, including Figures 4, 6, 7a-7d, 8, 9, 10a-10d, 11a-11b, 12, and 13a-13c.

[0191] Optionally, when the silicon photonic chip 1400 is an SOI silicon photonic chip, as shown in Figure 14, it may include a silicon substrate layer, a buried oxide layer and a top oxide layer stacked sequentially (for example, stacked from bottom to top as shown in the figure), with the waveguide structure buried in the top oxide layer and the bottom contacting the buried oxide layer.

[0192] In some scenarios, the layer containing the waveguide structure can also be called the waveguide layer. The waveguide layer is a layer buried in the top oxide layer and made of waveguide material. In this case, the silicon photonics chip 1400 includes a silicon substrate layer, a buried oxide layer, a waveguide layer, and a top oxide layer stacked sequentially, with the waveguide structure located in the waveguide layer.

[0193] The silicon photonics chip 1400 described above can be used in detection devices or systems with frequency modulation capabilities, such as the FMCW LiDAR mentioned above, or optical frequency domain reflectometry (OFDR) systems, optical coherence tomography (OCT) systems, etc., without any specific limitations.

[0194] Please refer to Figure 15, which shows a possible structural schematic diagram of a detection device provided in this application. The detection device 1500 may include the waveguide structure described above, or it may include the silicon photonic chip 1400 mentioned above, as shown in Figure 15.

[0195] Optionally, as shown in Figure 15, the detection device 1500 may further include a light source assembly 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, transmitted through the emitting component on the waveguide structure, and then emitted from the emitting end of the silicon photonic chip 1400.

[0196] Optionally, as shown in Figure 15, the detection device 1500 further includes a scanning component 1520, which scans the light signal emitted from the emitting end of the silicon photonics chip 1400 into the detection space. After the light signal illuminates 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 by the scanning component 1520 to the receiving end of the silicon photonics chip 1400. An echo signal generator (EC) can also be provided on the edge of the receiving end of the silicon photonics chip 1400. The echo signal is coupled to the waveguide structure of the silicon photonics 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 terminal of the silicon photonics chip 1400.

[0197] Further, optionally, as shown in FIG15, the detection device 1500 further includes a processing component 1531. The processing component 1531 is disposed on the electrical chip 1530. The input terminal of the electrical chip 1530 is connected between the electrical output terminal of the silicon photonic chip 1400 and the input terminal of the processing component 1531. Therefore, the electrical signal output by the electrical output terminal of the silicon photonic chip 1400 is transmitted to the processing component 1531. The processing component 1531 performs target detection based on the electrical signal, such as determining the distance and / or speed of the target.

[0198] Furthermore, alternatively, other components, such as an amplifier and an analog-to-digital converter (not shown), may also be included in the electrical chip 1530. The input of the amplifier is connected to the electrical output of the silicon photonics chip 1400, and the analog-to-digital converter is connected between the output of the amplifier and the input of the processing component 1531. The amplifier amplifies the electrical signal output by the silicon photonics chip 1400, and the analog-to-digital converter discretizes the amplified electrical signal, converts it into a digital signal, and outputs it to the processing component 1531, enabling the processing component 1531 to perform target detection based on the digital signal.

[0199] Optionally, as shown in Figure 15 above, the detection device 1500 may further include a window 1540, which is used to protect the various components inside the detection device 1500 and can transmit the light signal emitted by the detection device 1500.

[0200] It should be noted that the detection device architecture shown in Figure 15 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 any specific limitations in this regard.

[0201] Based on the structure and functional principle of the detection device described above, this application can also provide a terminal device, as shown in Figure 16. This terminal device 1600 may include the silicon photonics chip described above, or it may include the detection device 1500 described above, as shown in Figure 16.

[0202] Optionally, as shown in Figure 16, the terminal device 1600 may further include a processor 1610, which is used to call programs or instructions to control the operation of the detection device 1500. Furthermore, the processor 1610 may also receive target-related information from the detection device 1500. When the terminal device 1600 is a vehicle, the processor 1610 may also perform vehicle path planning, braking, or starting based on this acquired information. For example, the vehicle's position can be determined using latitude and longitude, or the vehicle's direction of travel and destination in the future can be determined using speed and orientation, or the number and density of obstacles around the vehicle can be determined using the distance to surrounding objects.

[0203] Furthermore, optionally, the terminal device 1600 may also include a memory 1620 for storing programs or instructions. Of course, the terminal device 1600 may also include other devices, such as wireless communication devices.

[0204] Processor 1610 may include one or more processing units. For example, 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. Different processing units may be independent devices or integrated into one or more processors.

[0205] The memory 1620 includes, but is not limited to, random access memory (RAM), flash memory, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), registers, hard disks, portable hard disks, CD-ROMs, or any other form of storage medium known in the art. Exemplarily, the storage medium is coupled to a processor, enabling the processor to read information from 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 reside within an ASIC.

[0206] For example, the terminal device 1600 mentioned above may be a vehicle (e.g., unmanned vehicle, intelligent vehicle, electric vehicle, or digital car), robot, surveying equipment, drone, smart home device (e.g., television, robot vacuum cleaner, smart lamp, audio system, smart lighting system, electrical control system, home background music, home theater system, intercom system, or video surveillance), smart manufacturing equipment (e.g., industrial equipment), smart transportation equipment (e.g., AGV, unmanned transport vehicle, or truck), or smart terminal (mobile phone, computer, tablet, PDA, desktop computer, headphones, audio equipment, wearable device, in-vehicle device, virtual reality device, augmented reality device, etc.).

[0207] 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 specific limitations on it.

[0208] In the above content, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. In the textual description of this application, the character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0209] Additionally, in this application, the terms "optionally" or "exemplary" are used to indicate that they are examples, illustrations, or descriptions. Any embodiment or design described as "optional" or "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or design options. Alternatively, it can be understood that the use of the terms "exemplary" or "optional" is intended to present concepts in a specific manner and does not constitute a limitation of this application.

[0210] It is understood that the various numerical designations used in this application are merely for descriptive convenience and are not intended to limit the scope of the embodiments of this application. The order of the process numbers described above does not imply the order of execution; the execution order of each process should be determined by its function and internal 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. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion, such as including a series of steps or units. A method, system, product, or device is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products, or devices.

Claims

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

2. The structure as described in claim 1, characterized in that, Both the first waveguide and the second waveguide are single-mode waveguides.

3. The structure as described in 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 as described in claim 1 or 2, characterized in that, The waveguide structure further 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 in which the waveguide structure is located, and 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 transmitted signals from the input optical signal; The second beam splitter is used to split at least two second transmitted signals from the input optical signal; 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 into the detection space by the scanning component for the purpose of detecting targets.

5. The structure as described in claim 4, characterized in that, The waveguide structure also includes a receiving component; The receiving component is used to acquire a local oscillator signal and an echo signal, and to 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 local oscillator signal is derived from the input signal, transmitted signal, or output signal of any of the following devices: the end-face coupler, the first waveguide, the second waveguide, the first beam splitter, or the second beam splitter.

6. The structure as described in claim 5, characterized in that, The end-face coupler also has a third output terminal, which outputs the local oscillator signal, and the receiving component is connected between the third output terminal and the receiving terminal of the chip.

7. The structure as described in claim 5, characterized in that, The second beam splitter also has another output terminal, and the receiving component is connected between the other output terminal and the receiving terminal of the chip; 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 terminal.

8. The structure as described in claim 5, characterized in that, 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 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 as described in claim 8, characterized in that, The beam splitting element is a directional coupler or a beam splitter.

10. The structure as described in claim 1 or 2, characterized in that, The end-face coupler, the first waveguide, and the second waveguide are located in the transmitting assembly, and there are N transmitting assemblies, where N is an integer greater than or equal to 2; The waveguide structure further includes a first beam combiner and a second beam combiner, both of which have N input terminals and at least two output terminals. The N input terminals of the first beam combiner are respectively connected to the output terminals of the N first waveguides in the N transmitting components, and the at least two output terminals of the first beam combiner are connected to at least two first transmitting terminals of the chip in which the waveguide structure is located. The N input terminals of the second beam combiner / splitter are respectively connected to the output terminals of the N second waveguides in the N transmitting components, and at least two output terminals of the second beam combiner / splitter are connected to at least two second transmitting terminals of the chip; The first beam combiner / splitter is used to combine N input optical signals into one beam and then split the beam into at least two first transmission signals; The second beam combiner / splitter is used to combine N input optical signals into one beam and then split the beam into at least two second transmitted signals; 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 into the detection space by the scanning component for the purpose of detecting targets.

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

12. The structure as described in claim 10, characterized in that, The waveguide structure also includes a receiving component; The receiving component is used to acquire a local oscillator signal and an echo signal, and to 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 local oscillator signal is derived from the input signal, transmitted signal, or output signal of any of the following devices: the end-face coupler of any transmitting component, the first waveguide of any transmitting component, the second waveguide of any transmitting component, the first beam combiner / splitter, or the second beam combiner / splitter.

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

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

15. The structure as described in claim 12, characterized in that, The receiving component has N components, and the waveguide structure also includes N beam splitting elements. The N beam splitting elements correspond one-to-one with the N transmitting components and the N receiving components. Each beam splitting element is coupled between the first waveguide of the corresponding transmitting component and the input end of the corresponding receiving component, or coupled between the second waveguide of the corresponding transmitting component and the input ends of the corresponding N receiving components. The N beam splitting elements are used to split the local oscillator signal from the optical signal transmitted in the coupled first or second waveguide, and output the local oscillator signal to the coupled receiving component.

16. The structure as described in any one of claims 5 to 9, 12 to 15, characterized in that, 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.

17. The structure as described in any one of claims 5 to 9, 12 to 15, characterized in that, The receiving component includes a fourth beam splitter and K mixers, where K is an integer greater than or equal to 2; the input of the fourth beam splitter is used to receive the local oscillator signal, the K outputs of the fourth beam splitter are connected to the K first inputs of the K mixers, and the K second inputs of the K mixers are connected to the K receiving terminals 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 a mixing operation on the K sub-local oscillator signals and the K echo signals received by the K receivers of the chip to obtain K intermediate frequency signals.

18. The structure as described in claim 17, characterized in that, The receiving component further includes a detection element connected between the output terminals of the K mixers and the electrical output terminal 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 photonics chip, characterized in that, Includes the waveguide structure as described in any one of claims 1 to 18.

20. The silicon photonics chip as described in 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 sequentially, with the waveguide structure located in the waveguide layer.

21. A detection device, characterized in that, Including the silicon photonics chip as described in claim 19 or 20.

22. The detection device as described in claim 21, characterized in that, It also includes a light source assembly; The light source component is used to emit optical signals to the silicon photonic chip, and the optical signals are coupled into the waveguide structure through the end-face coupler.

23. The detection device as described in claim 21 or 22, characterized in that, It also includes a scanning component; The scanning component is used to scan the optical signal emitted by the silicon photonic chip into the detection space.

24. The detection device as described in claim 21 or 22, characterized in that, It also includes a processing component 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 photonics chip.

25. A terminal device, characterized in that, Includes the detection device as described in any one of claims 21 to 24.

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