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

Abstract

A waveguide structure (400), a silicon optical chip, a detection apparatus, and a terminal device, relating to the technical field of sensors, and used for reducing a transmission loss of a waveguide caused by a TPA effect at a high optical power. The waveguide structure (400) comprises an edge coupler (EC); the EC comprises an input end (a11) and M first output ends (a121-a12M); the input end (a11) inputs a first optical signal (S11); the M first output ends (a121-a12M) output M second optical signals (S121-S12M); and the optical power of each of the M second optical signals (S121-S12M) is less than the optical power of the first optical signal (S11), M being an integer greater than or equal to 3. The EC can split one high optical power input into at least three low optical power outputs, so that when an output end of the EC is connected to a waveguide, all optical powers coupled into the EC are split into at least three waveguides, and thus the optical power for transmitting an optical signal in each waveguide can be reduced, high optical power density is not prone to occurring in each waveguide, and a TPA effect is not prone to occurring, thereby reducing an optical transmission loss.

Description

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

[0001] This application relates to the field of sensor technology, and in particular to lidar, the waveguide structure of lidar and silicon photonic chip, which can be applied to, but is not limited to, the field of transportation control. Background Technology

[0002] 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.

[0003] 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.

[0004] 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

[0005] 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.

[0006] In a first aspect, this application provides a waveguide structure including an end-face coupler. The end-face coupler includes an input end and M first output ends. The input end receives a first optical signal, and the M first output ends output M second optical signals. The optical power of each of the M second optical signals is less than the optical power of the first optical signal, where M is an integer greater than or equal to 3.

[0007] Based on the waveguide structure described above, the end-face coupler can transform a high-power input into at least three low-power outputs. Thus, when the output of the end-face coupler is connected to a waveguide, all the optical power coupled into the coupler will be distributed across at least three waveguides, preventing all optical power from being concentrated in a single waveguide. This reduces the optical power transmitted in each waveguide, making high optical power density less likely in each waveguide. 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 at least three optical signals through the end-face coupler, which, compared to existing technologies that use end-face couplers and at least two beamsplitters, saves on the number of beamsplitters 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.

[0008] In one possible design, the input of the end coupler has a first mode size, and the M first outputs have M second mode sizes, wherein the first mode size is larger than each of the M second mode sizes.

[0009] Based on the above design, the input of the end-face coupler is a large mode size, and the output is at least three small mode sizes. Therefore, the end-face coupler can transform a large mode input into at least three small mode outputs, thereby achieving beam splitting of optical power.

[0010] In one possible design, the waveguide structure also includes M first waveguides, which are connected to M first output terminals.

[0011] Based on the above design, the end-face coupler can connect to other components through M first waveguides, or realize the output transmission of optical signals.

[0012] In a further possible design, all M first waveguides are single-mode waveguides, and the mode spot size of the M first output terminals is the same as that of the single-mode waveguide. Single-mode waveguides have a smaller cross-sectional area 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.

[0013] In one possible design, the end-face coupler includes M strip-shaped units, each of the M strip-shaped units having a first end and a second end. The cross-sectional area of ​​the first end is less than a first set value, and the cross-sectional area of ​​the second end is greater than a second set value. The first set value is less than or equal to the second set value. The M first ends of the M strip-shaped units together serve as the input end of the end-face coupler, and the M second ends of the M strip-shaped units serve as the M first output ends of the end-face coupler.

[0014] Here, "strip unit" refers to a unit that is distributed in a long strip shape, that is, a unit that presents a long strip shape. This is for the understanding of those skilled in the art and is not specifically limited.

[0015] Based on the above design, the first end of each of the M strip units is used as a waveguide unit, while the second end is used as a different waveguide unit. Through the structure of the M strip units with one end larger than the other, the optical signal is absorbed from the smaller end to the larger end, realizing the transmission of the optical signal from the first end to the second end, while also reducing transmission loss.

[0016] In one example of the design above, the M strip units are an axisymmetric structure.

[0017] Based on the above example, the light transmission on both sides of the axis is exactly the same, which can achieve uniform transmission.

[0018] In one example of the above design, the spacing between adjacent strip units at the first end is less than a set spacing.

[0019] Based on the above example, adjacent strip units are positioned close enough at the first end that the first end can be considered as a whole, while the second end can be relatively far apart. In this way, when the optical signal is transmitted from the first end to the second end, it can be gradually absorbed into the interior of each strip unit and dispersed along each strip unit towards the second end.

[0020] Optionally, the M strip units can be placed in parallel, such as with the center lines of each strip unit being parallel, or they can be placed non-parallel, such as with one or more strip units being slightly tilted relative to the other strip units, or with some areas being slightly tilted, without limitation.

[0021] In one example of the above design, the M strip units have the same cross-sectional area at the first end. Under this structural design, the optical power of the second optical signal output by the strip units on both sides is less than the optical power of the second optical signal output by the strip unit in the middle.

[0022] Based on the above examples, it is possible to achieve the effect of high light output power in the middle area and low light output power in the two side areas. The detection distance in the middle area is longer, while the detection distance in the two side areas is relatively shorter. This is applicable to detection scenarios where the middle area is the region of interest (ROI).

[0023] In one example of the above design, the cross-sectional area of ​​the strip units on both sides at the first end is greater than that of the strip unit in the middle at the first end. Under this structural design, the optical power of the second optical signal output by the strip units on both sides is greater than or equal to the optical power of the second optical signal output by the strip unit in the middle.

[0024] Based on the above design, when the optical power of the second optical signal output from the strip units on both sides is equal to the optical power of the second optical signal output from the strip unit in the middle, the M first output ends of the waveguide structure emit light uniformly, and the M beams can be used to detect different regions at the same distance, resulting in equivalent detection capabilities for the M channels. Furthermore, since the end-face coupler equally divides the coupled first optical signal into M second optical signal outputs, ideally, the optical power density in each waveguide connected after the EC can reach 1 / M of the input optical power, effectively reducing the probability of TPA effect occurring in each waveguide.

[0025] In addition, when the optical power of the second optical signal output by the strip units on both sides is greater than the optical power of the second optical signal output by the strip unit in the middle, it can achieve the effect of high optical power output in the two side regions and low optical power output in the middle region. The detection distance in the two side regions is longer, while the detection distance in the middle region is relatively shorter. This is suitable for detection scenarios where the edge region is the region of interest.

[0026] In one example of the design above, each of the M strip units is a continuous structure.

[0027] Based on the above example, the first end of the M strip units will have a large pattern size in the first direction, which is the direction of the line connecting the first ends of the M strip units. Based on this large pattern size, the optical power per unit area is reduced compared to the prior art under the same optical power input, which can reduce the probability of the TPA effect.

[0028] In one example of the above design, some or all of the M strip units are subwavelength grating structures.

[0029] Based on the above examples, not only can the first ends of the M strip units have a large pattern size in the first direction, but a subwavelength grating structure can also be used to increase the pattern size of the first ends of the M strip units in the second direction, where the second direction is perpendicular to the first direction on the end face where the first ends are located. Based on this, the M strip units can achieve a two-dimensional large pattern. With this two-dimensional large pattern, under the same optical power input, the optical power per unit area is further reduced compared to a structure with a large pattern in one direction, thereby further reducing the probability of the TPA effect.

[0030] In a further possible example, when all M strip units are subwavelength grating structures, the M strip units include periodic regions.

[0031] Among them, the periodic region refers to the region where there is periodic change. For example, each strip unit is divided into independent parts, or there is a relatively thin part at the bottom connected to the top divided into independent parts, etc., as long as the period of change and the duty cycle are stable.

[0032] In a further possible example, when the M strip units are partially subwavelength grating structures, the M strip units include periodic regions, transition regions, and continuous regions, which are arranged along the direction from the first end to the second end of the M strip units.

[0033] Based on the above examples, the transition region can realize the transition of optical signals from the periodic region to the continuous region, avoid reflection caused by abrupt changes in refractive index, and reduce the transmission loss of optical signals.

[0034] In a further possible example, the periodic region includes multiple short blocks, and the continuous region includes long blocks that connect to the middle part of the multiple short blocks to form a transition region.

[0035] Based on the above examples, continuous regions and periodic regions can form a transition region at the connection point without the need to set up an additional transition region, resulting in lower process costs.

[0036] In one possible design, the end-face coupler and M first waveguides are located in the transmitting assembly, which may also include other structures, mainly including the following structure one and structure two.

[0037] In structure one, the M first output terminals of the end-face coupler are connected to the M transmitter terminals of the chip containing the waveguide structure. The M second optical signals serve as the M transmitter signals of the chip. The M transmitter signals are scanned to the detection space by the scanning component for target detection.

[0038] Based on the above structure, a transmitting component can be set in the waveguide structure. The M first output terminals of the end-face coupler are directly connected to the M transmitting terminals. Therefore, the M second optical signals output by the end-face coupler can be directly used as M transmitted signals without further processing by beam splitters or combiners, thus saving on the number of such components and reducing costs. Furthermore, the M transmitted signals can be used to jointly measure targets in the detection space. For example, the M transmitted signals can correspond to M detection channels, allowing the detection of M regions in a single scan, increasing the scanning range and improving detection efficiency.

[0039] In one example of structure one, the waveguide structure also includes a receiving component for acquiring a local oscillator signal and an echo signal, and mixing the local oscillator signal and the echo signal to obtain an intermediate frequency signal, which is used to determine the velocity and / or distance of the target, wherein the local oscillator signal is derived from the input signal, transmitted signal or output signal of the end coupler or any of the first waveguides.

[0040] 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.

[0041] In the above example, the local oscillator signal in the receiving component can be output using either of the following methods:

[0042] In the first splitting method, the end-face coupler also has a second output terminal, which outputs the local oscillator signal. The receiving component is connected between the second 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 M+1 optical signals, of which M optical signals are used as the transmitted signal, and the other optical signal is used as the local oscillator signal and mixed with the echo signal. In this way, the local oscillator signal and the transmitted signal are both separated from the same optical signal, resulting in the strongest signal correlation and the best subsequent mixing effect.

[0043] In the second separation method, the waveguide structure also includes a beam splitter element. This element is coupled between any of the first waveguides and the input of the receiving component. It is used to split the second optical signal transmitted through the coupled first waveguide into a local oscillator signal, and then output the local oscillator signal to the receiving component. Based on this second separation method, the local oscillator signal can be separated from the signal transmitted through the first waveguide using the beam splitter element. A portion of the optical signal transmitted in the first waveguide is separated as the local oscillator signal, while the remainder is directly used as the transmitted signal.

[0044] In one example of the above beam splitting method two, the beam splitting element can be a directional coupler or a beam splitter.

[0045] Based on the above examples, a directional coupler can couple the local oscillator signal from the first waveguide in a non-contact manner, while a beam splitter can be inserted into the first waveguide to directly split the local oscillator signal. Therefore, the waveguide structure can be applied to different beam splitting elements, improving flexibility and versatility.

[0046] 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 M beam combiners / splitters. Each of the M beam combiners / splitters has N input terminals and at least two first output terminals. The N input terminals are respectively connected to the output terminals of the N first waveguides in the N transmitting components, and the at least two first output terminals are connected to at least two transmitting terminals of the chip in which the waveguide structure is located. Each beam combiner / splitter is used to mix the components of the N input optical signals to obtain at least two transmitted signals and output them. All transmitted signals output by the M beam combiners / splitters are scanned to the detection space by the scanning component for target detection.

[0047] 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 and split by M beam combiners to form at least 2M transmitted signals. These at least 2M transmitted signals can be used to jointly measure and detect targets in the detection space. For example, at least 2M transmitted signals can correspond to at least 2M detection channels. In this way, at least 2M areas can be detected in a single scan, increasing the scanning range and improving detection efficiency.

[0048] In one example of structure two, optical signals from N emitting components have different wavelengths and / or different polarization states.

[0049] 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 a wider range and has a higher frequency. If different polarization states are used, multiple signals of the same wavelength can be used to detect the same distance, thereby improving the ranging capability.

[0050] In one example of structure two, 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, which is used to determine the velocity and / or distance of the target; wherein the local oscillator signal is separated from the input signal, transmitted signal, or output signal of the end face coupler of any transmitting component, the first waveguide of any transmitting component, or any beam combiner / splitter.

[0051] 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.

[0052] 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:

[0053] In the first splitting method, there are N receiving components, each corresponding one-to-one with one of the N transmitting components. Each transmitting component's end-face coupler also has a second output terminal, which outputs the local oscillator signal. Each receiving component is connected between the second 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 separated from the input signals of the end-face couplers of the N transmitting components. These N local oscillator signals have different wavelengths, and each signal is 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, every two transmitting signals have equal power, and the light output from every two detection channels is uniform.

[0054] In the second separation method, the M beam combiners / splitters include a first beam combiner / splitter. The first beam combiner / splitter also has a second output terminal. The receiving component is connected between the second output terminal and the receiving terminal of the chip. The first 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 second output terminal. Based on this separation method, there can be only one receiving component. The local oscillator signal of this 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 single mixing of the N-wavelength signal.

[0055] In the third separation method, there are N receiving components, and the waveguide structure also includes N beam splitters. These N beam splitters correspond one-to-one with the N transmitting components and the N receiving components. Each beam splitter is coupled between a first waveguide of its corresponding transmitting component and the input terminal of its corresponding receiving component. The N beam splitters are used to separate the local oscillator signal from the optical signal transmitted through the coupled first 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.

[0056] 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 each of the M second optical signals.

[0057] 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.

[0058] In one example of structure one or structure two above, the receiving component includes a beam splitter and M mixers. The input of the beam splitter is used to receive the local oscillator signal. The M outputs of the beam splitter are connected to the M first inputs of the M mixers. The M second inputs of the M mixers are connected to the M receiving terminals of the chip. The beam splitter is used to split the local oscillator signal into M sub-local oscillator signals and output the M sub-local oscillator signals to the M mixers. The M mixers are used to perform a mixing operation on the M sub-local oscillator signals and the M echo signals received by the M receiving terminals of the chip to obtain M intermediate frequency signals.

[0059] Based on the above example, the reception range of the echo signal can be increased by using M 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.

[0060] In a further possible example, the receiving component also includes a detection element connected between the outputs of the M mixers and the electrical output of the chip, for photoelectric detection of the M intermediate frequency signals, obtaining electrical signals and outputting them.

[0061] 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.

[0062] Secondly, this application provides a silicon photonics chip, including the waveguide structure described in the first aspect, any of the designs or examples above.

[0063] In one possible design, the silicon photonics chip includes a silicon substrate layer, a buried oxide layer, and a waveguide layer stacked sequentially, with the waveguide structure located in the waveguide layer.

[0064] 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.

[0065] In one example of the above design, the waveguide structure is exposed to air, where the refractive index is lower than that of the waveguide material.

[0066] Based on the above design, the thickness of the silicon photonics chip can be reduced, thus minimizing its footprint. Simultaneously, the low refractive index of air can reduce its impact on the transmission of optical signals through the waveguide structure.

[0067] In one example of the above design, the silicon photonics chip also includes an upper cladding layer, which is stacked on the waveguide layer. The waveguide structure is embedded in the upper cladding layer, and the refractive index of the material of the upper cladding layer is lower than that of the material of the waveguide structure.

[0068] Based on the above design, the upper cladding can protect the internal waveguide structure. At the same time, the low refractive index of the upper cladding material can reduce the impact on the transmission of optical signals in the waveguide structure.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] In one possible design, the detection device also includes a processing component disposed on the electrical chip for determining the distance and / or velocity of the target based on the electrical signal output by the silicon photonics chip.

[0073] 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.

[0074] 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

[0075] Figure 1 illustrates a possible application scenario to which this application applies;

[0076] Figure 2a illustrates a schematic diagram of a mainstream FMCWLiDAR launch architecture.

[0077] Figure 2b illustrates, for example, the optical power transmission of silicon photonics chips in mainstream FMCWLiDAR.

[0078] Figure 3 illustrates an exemplary structural diagram of a solution to the TPA effect in silicon photonics chips provided by the industry.

[0079] Figure 4 illustrates a schematic diagram of a waveguide structure provided in this application.

[0080] Figure 5 illustrates a possible structural diagram of an end-face coupler provided in this application;

[0081] Figure 6a illustrates a schematic diagram of a strip-shaped unit of a certain width and optical power distribution provided in this application;

[0082] Figure 6b illustrates a schematic diagram of another width of strip cell and optical power distribution provided in this application;

[0083] Figure 6c illustrates a schematic diagram of another type of strip cell with optical power distribution provided in this application;

[0084] Figure 7 illustrates a schematic diagram of possible connection shapes at both ends of a strip-shaped unit provided in this application;

[0085] Figure 8a illustrates a possible structural diagram of another end-face coupler provided in this application;

[0086] Figure 8b illustrates a possible structural diagram of another end-face coupler provided in this application;

[0087] Figure 9a illustrates a schematic diagram of another waveguide structure provided in this application;

[0088] Figure 9b illustrates a schematic diagram of another waveguide structure provided in this application;

[0089] Figure 9c illustrates a schematic diagram of another waveguide structure provided in this application;

[0090] Figure 10 illustrates a schematic diagram of a waveguide structure provided in Implementation Scheme 1.

[0091] Figure 11a 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 1.

[0092] Figure 11b 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.

[0093] Figure 11c exemplarily illustrates another structural schematic diagram of separating the local oscillator signal from the signal transmitted in the waveguide according to Scheme 1;

[0094] Figure 12 illustrates a schematic diagram of a receiving component provided in Embodiment 1;

[0095] Figure 13 illustrates a schematic diagram of a waveguide structure provided in Scheme 2;

[0096] Figure 14a illustrates 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 2;

[0097] Figure 14b illustrates 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 2.

[0098] Figure 14c illustrates an exemplary schematic diagram of a structure for separating a local oscillator signal from a signal transmitted through a waveguide, according to Embodiment 2.

[0099] Figure 14d illustrates an exemplary schematic diagram of another structure for separating the local oscillator signal from the signal transmitted through the waveguide, provided by Scheme 2.

[0100] Figure 15a illustrates a schematic diagram of a receiving component provided in Embodiment 2;

[0101] Figure 15b illustrates a schematic diagram of another receiving component provided in Implementation Scheme 2;

[0102] Figure 16 illustrates a schematic diagram of a waveguide structure provided in Embodiment 3;

[0103] Figure 17a is an exemplary schematic diagram of a waveguide structure including a receiving component provided in Embodiment 3;

[0104] Figure 17b is an exemplary schematic diagram of a waveguide structure including N receiving components provided in Implementation Scheme 3;

[0105] Figure 17c exemplarily illustrates a schematic diagram of another waveguide structure provided in Scheme 3, which includes N receiving components;

[0106] Figure 18a illustrates a possible structural diagram of a silicon photonic chip provided in this application;

[0107] Figure 18b illustrates a possible structural diagram of another silicon photonic chip provided in this application;

[0108] Figure 19 illustrates a possible structural diagram of a detection device provided in this application;

[0109] Figure 20 illustrates a schematic diagram of the structure of a terminal device provided in this application. Detailed Implementation

[0110] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0111] 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.

[0112] I. Silicon-on-insulator (SOI)

[0113] 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 and low power consumption.

[0114] II. Two-photon absorption (TPA) effect

[0115] The two-photon absorption (TPA) effect refers to the phenomenon where a molecule absorbs two photons simultaneously, transitioning 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 TPA effect occurs only under strong light and is a type of third-order nonlinear effect. For example, in lidar, the TPA 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 TPA 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.

[0116] III. Single-mode waveguide

[0117] 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.

[0118] IV. Edge Coupler (EC)

[0119] 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 does not perfectly match the MFD of a single-mode optical fiber. For example, for silicon photonic chips, the MFD of a single-mode waveguide is generally submicron, while the MFD of a single-mode optical fiber is 9-10 μm, a significant difference. Direct coupling would typically result in a coupling loss greater than 10 dB. Using an EC to couple the two devices allows for mode field matching, achieving higher coupling efficiency.

[0120] V. Pattern

[0121] 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.

[0122] VI. Subwavelength grating

[0123] Subwavelength gratings, also known as sub-wavelength gratings, are a type of metamaterial and an optical element with a subwavelength periodic structure. Compared to ordinary gratings, the period length of a subwavelength grating is not only much smaller than the wavelength of the incident light, but also significantly smaller than the period wavelength of a Bragg grating. Methods for realizing this structure include periodic surface nanostructures and subwavelength optical waveguides.

[0124] VII. Linearly polarized state

[0125] 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.

[0126] 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.

[0127] 8. Signal to Interference Plus Noise Ratio (SINR)

[0128] 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.

[0129] 9. Frequency mixing.

[0130] 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 related to the target distance. For example, in a static state, the absolute value of the frequency difference is proportional to the target distance. In a dynamic state, the IF signal also contains information about the Doppler effect caused by the target's movement, and the target's velocity can be calculated based on this Doppler effect information.

[0131] The preceding text introduced some of the terms used in this application. The following text introduces the possible application scenarios of this application.

[0132] 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.

[0133] 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.

[0134] 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.

[0135] 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.

[0136] Please refer to Figure 2a, which shows a schematic diagram of a mainstream FMCWLiDAR transmission 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 34 It 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.

[0137] 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.

[0138] 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 insertion loss (also known as 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. With the presence of the EC's own insertion loss, the optical power of the optical signal output by the EC is less than the optical power of the optical signal received by the EC. Typically, the insertion loss of the EC itself 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.

[0139] 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 insertion loss of the EC itself, 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 of ​​the device. 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 this single-mode waveguide B1, the optical signal is split into two single-mode waveguides B1. 21 B 22 Above, each single-mode waveguide B 21 B 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.

[0140] 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.

[0141] 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.

[0142] In view of this, this application provides a waveguide structure that uses a large-mode EC to directly split the input optical signal into three or more waveguides, thereby reducing the optical power density in each waveguide and lowering the probability of TPA effect. Compared with industry-provided solutions, this waveguide structure is entirely passive, requiring no additional semiconductor process steps, doping, or other additional processes and power consumption. Therefore, it solves the problems existing in the above-mentioned industry-provided solutions and has the advantages of simple process, low cost, low power consumption, and high reliability.

[0143] The waveguide structure and related schemes proposed in this application will be described in detail below with reference to Figures 4 to 20.

[0144] Please refer to Figure 4, which shows a schematic diagram of a waveguide structure provided in this application. The waveguide structure 400 includes an EC410, and the EC410 includes an input terminal a. 11 and M first output terminals, i.e., a 121 a 122 ... a 12MM is an integer greater than or equal to 3. The input terminal a... 11 Used to input the first optical signal S 11 M first output terminals a 121 ~a 12M Used to output M second optical signals, i.e., S 121 S 122 ... S 12M M second optical signals S 121 ~S 12M The optical power of each second optical signal in the signal is less than that of the first optical signal S. 11 The optical power.

[0145] Optionally, input terminal a of EC410 11 It has a first pattern size and M first output terminals a 121 ~a 12M The EC410 has M second modal sizes, where the first modal size is larger than each of the M second modal sizes. Based on this, the EC410 supports inputting a large modal, which, during transmission within the EC410, will be sent to M first output terminals a. 121 ~a 12M The input of a large mode pattern is coupled at the center and gradually becomes M smaller modes. In this way, the EC410 can transform a large mode pattern input into M smaller mode pattern outputs, and the EC410 can also be called a large mode pattern coupler.

[0146] Optionally, as shown in Figure 4, the waveguide structure 400 may further include M first waveguides, namely 511, 512, ..., 51M, with each of the M first waveguides 511 to 51M connected to one of the M first output terminals a of the EC410. 121 ~a 12M When the M first output terminals a of EC410 121 ~a 12M When there are M second mode spot sizes, the M second mode spot sizes are equal to the M first waveguide mode spot sizes. In other words, the second mode spot size of each first output terminal is equal to the mode spot size of the first waveguide to which it is connected.

[0147] Optionally, the first waveguide 511–51M 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. The cross-sectional dimensions of a single-mode waveguide are smaller than those of a multi-mode waveguide, resulting in a smaller footprint 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.

[0148] It is understandable that when the first waveguide 511 to 51M is a single-mode waveguide, the dimensions of the M second mode spots are all equal to the mode spot dimensions of the single-mode waveguide.

[0149] In one example, the EC410 can be composed of M strip cells, which are cells that are elongated in shape. These M strip cells support the reception of a large pattern, which, under the influence of the M strip cells, couples towards the center of the pattern, gradually transforming into M smaller patterns. If the size of the M smaller patterns is smaller than the size of the M second-order patterns, a transition section is needed to enlarge the size of the M smaller patterns. When the size of the M smaller patterns is equal to the size of the M second-order patterns, this position is designated as the M output terminals a of the EC410. 121 ~a 12M And it is connected to the M first waveguides 511 to 51M.

[0150] For ease of understanding, the following example, with M=4, provides two possible structures for EC410.

[0151] Structure 1

[0152] Please refer to Figure 5, which shows a possible structural schematic diagram of an EC410 provided in this application. Figure 5(A) shows a three-dimensional structural diagram of the EC410, and Figure 5(B) shows a top view of the EC410.

[0153] Referring to Figures 5(A) and (B), in this example, the EC410 includes four strip units ("1", "2", "3", and "4" in the figure). Each of the four strip units has a first end (left end in the figure) and a second end (right end in the figure). The cross-sectional area of ​​the first end is smaller than a first set value, while the cross-sectional area of ​​the second end is larger than a second set value, and the first set value is smaller than the second set value. In other words, the cross-sectional area of ​​each strip unit at its first end is smaller than the cross-sectional areas of itself and the other strip units at their second ends. The four first ends of the four strip units are combined to form the input terminal a of the EC410. 11 The four second terminals of the four strip units serve as the four first output terminals a of the EC410. 121 ~a 12M The first end of the four strip-shaped units is the entrance of EC410, and the second end is the exit of EC410.

[0154] As can be understood, as shown in Figure 5, with the height of the strip unit remaining constant, in the top view, each strip unit has a structure that is narrow at the first end and wide at the second end. The cross-sectional area of ​​the first end is smaller than a first predetermined value, and the cross-sectional area of ​​the second end is larger than a second predetermined value. In other words, the width of the first end is smaller than the first predetermined width, the width of the second end is larger than the second predetermined width, and the first predetermined width is smaller than the second predetermined width. The first predetermined value, the second predetermined value, the first predetermined width, and the second predetermined width are related to the material and cross-sectional area of ​​the strip unit. Strip units with different materials and different cross-sectional areas will have different predetermined values ​​or predetermined widths; specific limitations are not given here. Based on this structural design, after an optical signal is input to the first end of M strip units, it can be absorbed from the small first end to the large second end, realizing the transmission of the optical signal from the first end to the second end, while also having relatively low transmission loss.

[0155] Optionally, the four strip units can be placed parallel to each other, as shown in Figure 5, or they can be placed non-parallel, for example, one or more strip units may be tilted relative to the other strip units, or a portion of them may be tilted; this is not limited. Here, parallel means that the center lines of the M strip units are parallel or approximately parallel. The center lines of the four strip units can be seen as the dashed line shown in Figure 5(B), which is perpendicular to the XY plane shown in Figure 5(A). The direction of this dashed line is also called the light propagation direction.

[0156] Optionally, the spacing between adjacent strip units at their first ends is less than a predetermined spacing. That is, adjacent strip units are sufficiently close at their first ends so that the first ends of the M strip units can be considered as a single end, while their second ends can be relatively far apart. In this way, when the optical signal is transmitted from the first end to the second end, it can be gradually absorbed into the interior of each strip unit and dispersed along each strip unit towards the second end. The value of the predetermined spacing is related to the material of the strip units; strip units made of different materials will have different predetermined spacings, and no specific limitation is given here.

[0157] Optionally, the structures of the four strip units can be completely identical or not completely identical; for example, they can be completely different, or partially identical and partially different. In the case of non-identical structures, in one example, to ensure the uniformity of light output at the exit, the four strip units can be designed to be axially symmetrical, such as the top two strip units and the bottom two strip units being axially symmetrical. This ensures uniform light output from the top two exits and the bottom two exits, and a uniform beam facilitates subsequent detection and processing.

[0158] Understandably, the structure of a strip unit is determined by two parameters: the cross-sectional area at both ends and the shape of the connection between the two ends. By designing one or more of these two parameters, various different optical power distributions can be flexibly designed at the second end of the four strip units.

[0159] Cross-sectional area

[0160] Optionally, when the second ends of the four strip units are all connected to a single-mode waveguide, the cross-sectional area of ​​the four strip units at the second ends is the same as the cross-sectional area of ​​the single-mode waveguide, while the cross-sectional areas of the four strip units at the first ends can be the same or different.

[0161] Assuming the four strip-shaped units have the same height at their first end cross-sections in the Y direction, the cross-sectional area of ​​each unit at its first end can be represented by its width in the X direction. When the widths of the first end cross-sections in the X direction are the same or different, the four strip-shaped units will correspond to different optical power distributions. For ease of understanding, three possible widths and optical power distribution forms are given below.

[0162] As an example, as shown in Figure 6a(A), when the four stripe units have the same width at their first ends, that is, when the cross-sectional areas of the four stripe units at their first ends are the same, as shown in Figure 6a(B), a large-pattern optical signal is input from the first ends of the four stripe units. This large-pattern optical signal is more concentrated in the middle region. Therefore, the first ends of the two middle stripe units "2" and "3" receive more optical power, while the first ends of the two outer stripe units "1" and "4" receive less optical power. The optical signal received at the first end of each stripe unit is absorbed into the wide part of the stripe unit, coupled to the center of the pattern of the stripe unit, and then transmitted to the second end of the stripe unit. Because the first ends of the two middle stripe units "2" and "3" absorb more optical power, the second ends of the two middle stripe units "2" and "3" have greater optical power, while the second ends of the two outer stripe units "1" and "4" have less optical power. This structural design achieves the effect of high light intensity from the central detection channel and low light intensity from the edge detection channels. The central detection channel can detect farther distances, while the edge detection channels can detect relatively closer distances. This structure is more suitable for detection scenarios where the central area is the region of interest.

[0163] As another example, as shown in Figure 6b(A), when the width of the two outer strip units "1" and "4" at their first ends is larger than the width of the two middle strip units "2" and "3" at their first ends—for example, the width of the two outer strip units "1" and "4" at their first ends is larger than that in Figure 6a(A), and / or the width of the two middle strip units "2" and "3" at their first ends is smaller than that in Figure 6a(A)—then, as shown in Figure 6b(B), although the optical signal of a large pattern spot would originally be more concentrated in the middle region, because the cross-sectional area of ​​the first ends of the two outer strip units "1" and "4" is larger, the optical signal that can be received at the first ends of the two outer strip units "1" and "4" is greater than that shown in the structure in Figure 6a(A). By testing different cross-sectional areas and beam reception conditions, it is possible to find a combination of cross-sectional areas that makes the optical power received by the four strip units at their first ends approximately the same. Based on this cross-sectional area combination, after the optical signal is transmitted to the second end of the four strip units, the optical power emitted from the second end of the four strip units can be the same or approximately the same, thereby achieving the effect of uniform light output from the four detection channels.

[0164] Taking the same example, based on the four strip-shaped unit structures shown in Figure 6b(A), the coupled first optical signal S can be... 11 Equal power is divided into M second optical signals S 121 ~S 12M Therefore, all optical power coupled into the EC410 is evenly distributed to the M first output terminals a. 121 ~a 12M In the middle, if there are M first output terminals a 121 ~a 12M Following M first waveguides, the optical power density in each first waveguide is only 1 / M of that in existing schemes. Based on this, with the same optical power density in a single first waveguide, the density of the first optical signal coupled to the EC410 can be much greater than in existing technologies. 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 optical transmission loss caused by the TPA effect in the waveguides. With other parameters unchanged, for the same target detection distance, its detection SNR can be significantly improved, and for the same detection SNR, its target ranging capability can be significantly improved; regardless of the parameters, its detection performance can be effectively improved.

[0165] As another example, as shown in Figure 6c(A), when the width difference between the two outer stripe units "1" and "4" at their first ends and the two middle stripe units "2" and "3" at their first ends becomes larger—for example, when the width of the two outer stripe units "1" and "4" at their first ends continues to increase compared to Figure 6b(A), and / or when the width of the two middle stripe units "2" and "3" at their first ends continues to decrease compared to Figure 6b(A), as shown in Figure 6c(B), a large-pattern optical signal is received more by the first ends of the two outer stripe units "1" and "4," and less by the first ends of the two middle stripe units "2" and "3." Therefore, after the optical signal is transmitted to the second ends of the four stripe units, the optical power emitted from the second ends of the two outer stripe units "1" and "4" is greater than the optical power emitted from the second ends of the two middle stripe units "2" and "3." This structural design achieves the effect of high light intensity from the edge detection channels and low light intensity from the middle detection channels. The edge detection channels can detect farther distances, while the middle detection channels can detect relatively closer distances. This structure is more suitable for detection scenarios where the edge region is the region of interest.

[0166] It is understood that Figures 6a to 6c are merely illustrative examples of optical transmission forms corresponding to three different width relationships of strip units, but this application does not limit the four strip units to having this width relationship. In other examples, these width relationships can also be replaced by height relationships, or width relationships and height relationships together, as long as the cross-sectional area of ​​the first end meets the size shown in Figures 6a to 6c. Alternatively, in some further examples, other optical power distribution schemes can be obtained by adjusting one or more of the width and / or height. For example, by increasing the cross-sectional area of ​​the middle strip unit at the first end, almost all the optical power can be concentrated in the middle strip unit, or by further increasing the cross-sectional area of ​​the two side strip units at the first end, almost all the optical power can be concentrated in the two side strip units, and so on. This application will not list them all.

[0167] Connecting shapes

[0168] It is understandable that for any strip-shaped unit, the cross-sectional area of ​​its first end is smaller than that of its second end. Therefore, the overall shape of the connection between the first end and the second end shows that the cross-sectional area tends to increase from the first end to the second end. As for how the increasing trend is achieved through connection, this application does not make any specific limitation.

[0169] For example, as shown in Figure 5, assuming that the height of the strip unit in the Y direction remains constant, from the top view, the shape between the first end and the second end gradually changes from narrow to wide from left to right. The middle gradually changing part serves as the transition part, and the mode size of the last wide part is the second mode size. If the first waveguide connected is a single-mode waveguide, then it is equal to the mode size of the single-mode waveguide.

[0170] The connection between the first and second ends can be achieved through one or more of the following: a straight line, a diagonal line, a curve, or a broken line. For example, the first and second ends can be directly connected by a diagonal line as shown in Figure 7(A), making the strip unit appear as a trapezoid. Alternatively, they can be connected by a curve as shown in Figure 7(B). Or, they can be connected by a straight line and a diagonal line as shown in Figure 7(C), where the cross-sectional area of ​​the section connected by the straight line remains unchanged, while the cross-sectional area of ​​the section connected by the diagonal line gradually increases. Or, they can be connected by two diagonal lines as shown in Figure 7(D), where the increasing trend of the cross-sectional area of ​​the first diagonal line connection is less than that of the second diagonal line connection.

[0171] Of course, there are other connection forms, such as connecting a curve and a straight line, or connecting a curve and a diagonal line, or even dividing it into three or more segments, at least one of which has a tendency to increase the cross-sectional area, etc., which will not be listed here.

[0172] It should be noted that Figure 7 only shows the connection shape of one strip unit. When four strip units are included, the connection shapes of the four strip units can be the same or different. For example, when the four strip units are designed as an axisymmetric structure, the connection shapes of strip units "1" and "4" are the same, the connection shapes of strip units "2" and "3" are the same, while the connection shapes of strip units "1" and "2" can be the same or different, without limitation.

[0173] Furthermore, Figures 6a to 6c show different optical density distributions achieved by designing different cross-sectional areas at the first end of each strip unit. However, these optical density distributions can also be achieved by designing various morphological variations in the connection portions at both ends of each strip unit. For example, different strip units can be designed with different connection shapes, or different cross-sectional areas at the first end and different connection shapes. In one example, based on the desired optical density distribution, various connection shapes and cross-sectional areas can be designed in advance and tested to find the most suitable connection shape and cross-sectional area for the desired optical density distribution, which can then be used as structural parameters for fabricating each strip unit. This application will not elaborate on this aspect.

[0174] Structure 2

[0175] The EC410 in Structure 2 is similar to that in Structure 1. Overall, the EC410 in Structure 2 also has M strip units. The difference is that each of the M strip units in Structure 1 is a continuous block, such as a continuous trapezoidal block of the same height (belonging to a homogeneous medium), while the M strip units in Structure 2 contain a subwavelength grating structure (belonging to a metamaterial).

[0176] Optionally, in structure two, some or all of the M strip units are subwavelength grating structures. There are two possible configurations: one configuration, as shown in Figure 8a, includes subwavelength grating structures throughout the entire structure; the other configuration, as shown in Figure 8b, includes subwavelength grating structures only in the first end and subsequent regions.

[0177] Optionally, in the first configuration, as shown in Figure 8a, each of the M strip units is composed of a periodic region. A periodic region refers to a region exhibiting periodic variation; the period here needs to be sufficiently small, typically smaller than the period of a Bragg grating, to form a subwavelength grating structure. In detail, each strip unit can include a series of short blocks, and multiple short blocks collectively present the shape of a strip unit in Structure 1, achieving the function of the strip unit in Structure 1 described above.

[0178] It should be noted that the individual short blocks can be discrete or non-discrete, with Figure 8a using the former as an example. Discrete means that the different short blocks are completely disconnected, while non-discrete means that the different short blocks are not completely disconnected, for example, a portion at the bottom may be connected. This is equivalent to having many through slots cut into a single structure, forming rows of structures, but the bottoms of these rows are connected by relatively thin sections. Of course, there could be other structures, such as partially completely disconnected, partially connected at the bottom, or connected in the middle, etc., without any specific limitations.

[0179] Optionally, in the second configuration, as shown in Figure 8b, each of the M strip units includes a periodic region, a transition region, and a continuous region, arranged along the direction from the first end to the second end. One end of the transition region is connected to the periodic region, and the other end is connected to the continuous region, enabling the transition of the optical signal from the periodic region to the continuous region. For example, in one possible implementation, as shown in Figure 8b, the periodic region includes multiple short blocks, and the continuous region includes long blocks. The long blocks connect to the middle portions of the multiple short blocks, forming the transition region. In this way, the continuous region and the periodic region themselves can form a transition region at the connection point, eliminating the need for an additional transition region and reducing manufacturing costs.

[0180] It should be noted that, in the second form, the periodic region can be completely disjointed blocks, meaning multiple short blocks are discretely separated, or it can be partially disjointed blocks, such as multiple short blocks having a thin section connected at the bottom (or center region or top, etc., without limitation), or some short blocks being connected while the remaining short blocks are completely disjointed, and so on. There are many possible structures, as long as they can form a subwavelength grating structure; this application does not impose specific limitations on this.

[0181] Furthermore, in the second configuration, the periodic region, transition region, and continuous region must typically be arranged sequentially, and the periodic region cannot be designed after the continuous region. Therefore, the periodic region must always start from the first end, and the length of the periodic region can be designed according to actual needs. For example, it could be designed as a periodic region for 1 / 3 of the length starting from the first end, or it could be designed as a periodic region for 2 / 3 of the length starting from the first end, or it could be designed as a periodic region for 3 / 4 of the length starting from the first end, etc., without any specific limitations.

[0182] It should be noted that if the strip units are designed as continuous blocks as shown in Figure 5, the first end of each strip unit has a large pattern size in the X direction. Based on this large pattern size, with the same input optical signal power, the optical power received per unit area by each strip unit is smaller compared to the prior art, and the probability of TPA effect is also reduced. Furthermore, if designed as the structure shown in Figure 8a or Figure 8b, the pattern size of the first end of each strip unit in the Y direction can be increased using a subwavelength grating structure. In other words, each strip unit not only has a large pattern size in the X direction but also in the Y direction (compared to the structure shown in Figure 5). The first end of each strip unit supports a two-dimensional large pattern size. Based on this large pattern size, with the same input optical signal power, the optical power received per unit area by each strip unit is further reduced, and the probability of TPA effect is further reduced.

[0183] Based on the EC410 structure described above, the input optical signal can be directly split into three or more waveguides, reducing the optical power in a single waveguide and making it less prone to high optical power density 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 less likely to generate the TPA effect, thus solving 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 through 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.

[0184] It is understood that the above content only presents two possible structures of the EC410, and the EC410 can also have other structures. Any coupler that can realize a large input pattern and output three or more small patterns can be used as the EC410 in this application, and this application does not make any specific limitations on it.

[0185] The above content provides a detailed introduction to the structure of EC 410. The following section will explain the other components in the waveguide structure.

[0186] Optionally, the waveguide structure 400 can be located on a chip, such as an SOI silicon photonics chip. The chip includes at least one transmitter, and the number of at least one transmitter can have various possible relationships with the number of M first output terminals in the EC410, for example:

[0187] Scenario 1: The number of at least one transmitter is less than the number of M first output terminals. For example, as shown in Figure 9a, the chip has MK (K is an integer less than M) transmitters, namely b1, b2, ..., b... M-K The EC410 has M first output terminals a 121 ~a 12M In this case, the waveguide structure 400 can also be equipped with a beam combiner / splitter (or beam combiner), which is connected to the M first output terminals a. 121 ~a 12M and MK transmitters b1~b M-K Between, used to connect M first output terminals a 121 ~a 12M The output of M second optical signals S 121 ~S 12M Mixing the components, for example, combining M second optical signals S121 ~S 12M Each 1 / M component is mixed into a single transmission signal, resulting in MK transmission signals, which are then output from MK transmitters. The optical power of the MK transmission signals can be the same or different, without limitation. Optionally, other implementations are possible; for example, a beam combiner / splitter (or beam combiner) can be connected to fewer than M first outputs to combine or split the second optical signals output from the connected first outputs into one or more transmission signals. Regardless of the implementation method, as long as MK beams of transmission signals can be output through the EC410 and beam combiner / splitter, this application does not impose specific limitations.

[0188] Scenario 2: The number of at least one transmitter is greater than the number of M first output terminals. For example, as shown in Figure 9b, the chip has M+K transmitter terminals, namely b1, b2, ..., b... M ... b M+K The EC410 has M first output terminals a 121 ~a 12M In this case, a beam splitter can also be provided in the waveguide structure 400, and the beam splitter is connected to the first output terminal a. 12M and K+1 transmitters b M ~b M+K Between, used to connect the first output terminal a 12M The output second optical signal S 12M It is divided into K+1 transmitted signals, and another M-1 first output terminals a 121 ~a 12M-1 It is then directly connected to M-1 transmitting terminals, so that the output of M-1 second optical signals S 121 ~S 12M-1 The signal can be directly transmitted as M-1 signals. Alternatively, other implementations are possible. For example, a beam splitter can be connected to each of the multiple first output terminals, with each beam splitter dividing the second optical signal output from the connected first output terminal into at least two transmitted signals. Alternatively, a beam combiner / splitter can be connected to some or all of the first output terminals, mixing some or all of the components of the second optical signal to obtain more transmitted signals. Regardless of the implementation method, as long as M+K transmitted signals can be output through the EC410 and beam splitter, this application does not impose specific limitations on this.

[0189] Scenario 3: The number of at least one transmitter is equal to the number of M first output terminals. For example, as shown in Figure 9c, the chip has M transmitter terminals b1 to b2. M The EC410 also has M first output terminals a 121 ~a 12MIn this case, M first output terminals a 121 ~a 12M-1 It can be directly connected to M transmitters b1 to b M Above, so that the output M second optical signals S 121 ~S 12M It can be directly used as M transmitted signals. In this case, the EC410 structure provided in this application can directly realize the conversion from the input end to the multiple transmitter end, without the need to set up additional beam splitting or beam combining elements to split more transmitted beams or combine fewer transmitted beams. This can reduce the number of beam splitting or beam combining elements, reduce structural complexity, and save costs.

[0190] To facilitate the introduction of the scheme, the following uses scenario three as an example to further illustrate the other components in waveguide structure 400.

[0191] In the waveguide structure 400 shown in Figure 4, EC410 and M first waveguides 511 to 51M can be 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 to three.

[0192] Implementation Plan 1: Includes a launch component.

[0193] Please refer to Figure 10, which shows a schematic diagram of a waveguide structure provided in Implementation Scheme 1. In this example, it is assumed that the chip has M transmitters b1 to b2. M The EC410 has M first output terminals a 121 ~a 12M Then there are M first output terminals a 121 ~a 12M M first waveguides 511 to 51M can be directly connected to M transmitters b1 to b M Above. Based on this connection, the M first output terminals a of the EC410 121 ~a 12M The output of M second optical signals S 121 ~S 12M It will be transmitted to M transmitters b1 to b through M first waveguides 511 to 51M. M The signals are transmitted as M signals to the scanning component, and then scanned by the scanning component into the detection space.

[0194] Optionally, M transmitted signals are used to measure the target. For example, M transmitted signals can correspond to M detection channels, and the M transmitted signals are scanned into M regions by subsequent scanning components. In this way, M regions can be detected in a single scan, increasing the scanning range and improving detection efficiency. Each region can be a point, line, or surface, etc., without limitation.

[0195] Optionally, when each strip unit in the EC410 has an axisymmetric structure, the EC410 outputs M second optical signals S 121 ~S 12M The signals are divided into two symmetrical groups (M is an even number; if M is odd, they are divided into three groups, with the second optical signal in the middle group being a separate group), and the intensity of the second optical signal at corresponding positions in both groups is the same. Since there are M second optical signals S... 121 ~S 12M Since the M signals are directly transmitted, they are divided into two groups. The light intensity of the transmitted signals at corresponding positions in the two groups is the same, and they can reach the same distance in the detection space, so the ranging capability is consistent.

[0196] In one example, when the strip cells in the EC410 have the structure shown in Figure 6a, the middle strip cell has a higher output power, while the outer strip cells have a lower output power. Therefore, the transmission signal power in the middle region is higher, and the transmission signal power in the edge region is lower. This results in a longer detection range in the middle region and a relatively shorter detection range in the edge region. Alternatively, when the strip cells in the EC410 have the structure shown in Figure 6c, the outer strip cells have a higher output power, while the middle strip cells have a lower output power. Therefore, the transmission signal power in the edge region is higher, and the transmission signal power in the middle region is lower. This results in a longer detection range in the edge region and a relatively shorter detection range in the middle region. These two structures can detect different regions of interest.

[0197] In another example, when the strip units in EC410 have the structure shown in Figure 6b above, since the light output power of each strip unit is the same or approximately the same, the transmission power of each transmitted signal is the same or approximately the same, and each transmitted signal can reach the same distance in the detection space, thereby obtaining the detection results of different areas at the same distance, and the ranging capability of each channel is consistent.

[0198] Optionally, as shown in Figure 10, the waveguide structure 400 may further include a receiving component 610, which is used to acquire the local oscillator signal S. 13 and echo signal S 14 And the local oscillator signal S 13 and echo signal S 14Frequency 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 610 can receive the echo signal S from the receiving terminal c1 of the chip. 14 For example, one input terminal of the receiving component 610 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. 14 The signal is then transmitted back to the receiving terminal c1 of the chip, allowing the receiving component 610 to receive the echo signal S from the receiving terminal c1. 14 .

[0199] In addition, the local oscillator signal S 13 It can be distinguished from the input signal, transmitted signal, or output signal of any of the devices in EC410 and the first waveguides 511 to 51M. For ease of understanding, two possible examples are given below.

[0200] Example 1, please refer to Figure 11a, which shows the local oscillator signal S. 13 A possible structural diagram derived from the input signal of the EC410. In this structure, the EC410 also has a second output terminal a. 13 (For example, EC410 also includes the (M+1)th strip unit. The structure of the (M+1)th strip unit is described above in the introduction of the structure of the first M strip units, and will not be repeated here.) One input terminal of the receiving component 610 is connected to the receiving terminal c1 of the chip, and the other input terminal is connected to the second output terminal a of EC410. 13 Up. EC410 receives the first optical signal S. 11 Then, the first optical signal S 11 Coupled to M first output terminals a 121 ~a 12M Second output terminal a 13 Above, where M are first output terminals a 121 ~a 12M Output M second optical signals S 121 ~S 12M Second output terminal a 13 Output local oscillator signal S 13 The receiving component 610 receives data from the second output terminal a. 12 Received local oscillator signal S 13 .

[0201] Optionally, the local oscillator signal S 13 The optical power is less than M second optical signals S 121 ~S 12M The optical power of each second optical signal in the EC410. For example, the EC410 will convert the first optical signal S... 11 A relatively low-power optical signal is coupled to the second output terminal a. 13The remaining high-power optical signal is coupled to the M first output terminals a through power sharing or uneven distribution. 121 ~a 12M Up. In this way, the M transmitted signals will have relatively high transmission power, while the local oscillator signal S... 13 It has relatively low power consumption, which reduces the amount of local oscillator signal S extracted from the EC410. 13 The impact on the transmitted signal.

[0202] Optionally, referring to Figures 5 and 6a to 6c above, if the third output terminal is implemented through the (M+1)th strip unit, then in order to make the local oscillator signal S 13 Since the optical power is relatively low, the cross-sectional area of ​​the (M+1)th strip unit at its first end can be designed to be smaller than that of the other M strip units at their first ends, and / or the (M+1)th strip unit can be positioned at the edge. In this way, the optical power received at the first end of the (M+1)th strip unit is smaller than that of the other M strip units. After the optical signal is transmitted to the second end of the (M+1)th strip unit, the output is the local oscillator signal S. 13 Local oscillator signal S 13 The optical power is also relatively small.

[0203] Optionally, the receiving component 610 can be connected to the second output terminal a via a waveguide, optical fiber, or other means capable of transmitting optical signals. 13 Above. For example, Figure 11a shows a waveguide connection, in which case the second output terminal a of the EC410... 13 It can also have a second mode size. When the waveguide is a single-mode waveguide, the second output terminal a 13 The mode size is the same as the mode size of the single-mode waveguide. In other words, the mode size of the (M+1)th strip unit at the second end is equal to the mode size of the single-mode waveguide, and the cross-sectional area of ​​the (M+1)th strip unit at the second end is equal to the cross-sectional area of ​​the single-mode waveguide.

[0204] Example 2, see Figures 11b and 11c, showing the local oscillator signal S. 13 Two possible structural diagrams can be derived from the signal transmitted by the first waveguide 51M. The first waveguide 51M can also be replaced by any other first waveguide, without limitation. In this structure, the waveguide structure 400 further includes a beam splitter 710, which is coupled or connected between the first waveguide 51M and another input terminal of the receiving component 610. The beam splitter 710 is used for the second optical signal S transmitted from the first waveguide 51M. 12M The split beam is the local oscillator signal S 13 and the local oscillator signal S 13 The output is sent to the receiving component 610. In this case, the output is sent to the transmitting end b. M The optical power of the optical signal is less than that of the first output terminal a of EC410.12M The output second optical signal S 12M Optical power. Optionally, the local oscillator signal S 13 The optical power is less than the output to the transmitter b M The optical power of the optical signal. For example, the beam splitter 710 receives the optical power of the second optical signal S. 12M The lower-power optical signal is separated and output to the receiving component 610, while the remaining high-power optical signal is output to the transmitting end b. M .

[0205] The beam splitter 710 can be a directional coupler, as shown in Figure 11b. This directional coupler does not contact the first waveguide 51M, but is relatively close to it. In other words, a directional coupler can be placed sufficiently close to the first waveguide 51M, allowing the directional coupler to transmit the second optical signal S from the first waveguide 51M. 12M The local oscillator signal S is split into two signals with unequal power. 13 Alternatively, the beam splitter 710 can also be a beam splitter, as shown in Figure 11c. This beam splitter is directly inserted in the middle of the first waveguide 51M, splitting the second optical signal S transmitted in the first waveguide 51M. 12M The spectral dispersion is the local oscillator signal S. 13 And transmit signals.

[0206] Understandably, the two examples above are only for illustrating how to extract the local oscillator signal S from the input signal. 13 Several possible structures are given, and other branched structures can be deduced by analogy with the above structures, which will not be repeated here.

[0207] Optionally, the receiving component 610 can be any component or combination thereof capable of performing mixing. For example, taking the structure shown in Figure 11b as an example, please refer to Figure 12, which shows a specific structural schematic diagram of a receiving component provided in Embodiment 1. Combining Figures 11b and 12, in this example, the receiving component 610 includes a beam splitter 611 and K mixers, where K is an integer greater than or equal to 2. In Figure 12, taking K=M as an example, the receiving component 610 includes M mixers, namely mixers 6121, 6122, ..., 612M. The beam splitter 611 has one input terminal and M output terminals. The input terminal is the input terminal of the receiving component 610, used to acquire the local oscillator signal S. 13 The M output terminals are respectively connected to the M first input terminals of the M mixers 6121 to 612M, and the M second input terminals of the M mixers 6121 to 612M are connected to the M receiving terminals c of the chip. 11 c 12 ... c 1MHere, the connections between the various components can be achieved through waveguides, optical fibers, or other means that can transmit optical signals. Figure 12 shows a waveguide connection as an example.

[0208] Based on this structure and connection, the input of beam splitter 611 can receive the local oscillator signal S. 13 The beam splitter 611 splits the local oscillator signal S 13 Spectroscopy (e.g., equal power splitting) results in M ​​sub-local oscillator signals S. 131 S 132 ... S 13M And through its M output terminals, these M sub-local oscillator signals S 131 ~S 13M The outputs are distributed to M mixers 6121 to 612M. These M mixers 6121 to 612M can also receive signals from the chip's M receivers c. 11 ~c 1M Received M echo signals S 141 S 142 ... S 14M Each mixer performs a mixing operation on the received sub-local oscillator signal and echo signal to generate its own intermediate frequency signal. The M intermediate frequency signals generated by the M mixers 6121 to 612M are used to jointly determine the distance and / or velocity of the target; in other words, they jointly achieve target measurement.

[0209] Optionally, the M mixers 6121-612M, together with subsequent components, achieve target measurement. For example, as shown in Figures 11b and 12, the receiving component 610 may further include a detection element 613. The detection element 613 is connected between the output terminals of the M mixers 6121-612M and the electrical output terminal (d) of the chip, and is used to perform photoelectric detection on the M intermediate frequency signals generated by the M mixers 6121-612M to obtain and output electrical signals. 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.

[0210] It should be noted that there can be only one detector element 613, or there can be M detector elements, with each of the M detector elements corresponding to one of the M mixers. Each mixer is connected to its corresponding detector element. In this case, each detector element only performs photoelectric detection on the intermediate frequency signal generated by the mixer it is connected to. Alternatively, there can be more than or equal to two but less than M detector elements; no specific limitation is made here.

[0211] Optionally, a transmitting component is used to transmit an optical signal of one wavelength. In embodiment one, since the waveguide structure 400 includes a transmitting component, the M transmitted signals have the same wavelength, and the M sub-local oscillator signals S131 ~S 13M 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 other wavelength signals are treated as noise signals and are not used. Therefore, the M intermediate frequency signals are all signals with the same wavelength as the transmitted signal. Based on these M intermediate frequency signals, the measurement accuracy can be improved.

[0212] 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.

[0213] Implementation Plan 2: Includes two launch components.

[0214] Please refer to Figure 13, 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 EC and M first waveguides as described above. For example, as shown in Figure 13, one transmitting component includes EC410 and M first waveguides 511 to 51M, and the other transmitting component includes EC420 and M first waveguides 521, 522, ..., 52M. In this case, the waveguide structure 400 also includes M beam combiners and splitters, namely beam combiners and splitters 810, 820, ..., 8M0. The chip containing the waveguide structure 400 may include one or more transmitters. Figure 13 uses an example with 2M transmitters, i.e., transmitter b. 11 b 12 b 21 b 22 ... b M1 b M2 Each of the M beam combiners / splitters 810 to 8M0 has two input terminals and two output terminals. The two input terminals of each beam combiner / splitter are connected to the output terminals of any two first waveguides in the two transmitting components, and the two output terminals of each beam combiner / splitter are connected to the two transmitting terminals of the chip. For example, the two input terminals of beam combiner / splitter 810 are connected to the output terminals of first waveguide 511 and first waveguide 521, respectively, and the two output terminals are connected to the transmitting terminal b of the chip. 11 b 12 The two input terminals of the beam combiner / splitter 820 are connected to the output terminals of the first waveguide 512 and the first waveguide 522, respectively, and the two output terminals are connected to the transmitter terminal b of the chip. 21 b 22The two input terminals of the beam combiner / splitter 8M0 are connected to the output terminals of the first waveguide 51M and the first waveguide 52M, respectively. The two output terminals are connected to the transmitter terminal b of the chip. M1 b M2 .

[0215] Based on this structure and connection, in the transmitting component above, the EC410 receives the first input optical signal S. 11 The beam is split into M second optical signals S 121 S 122 ... S 12M The second optical signal S 121 The second optical signal S is transmitted through the first waveguide 511 to the beam combiner / splitter 810. 122 After being transmitted through the first waveguide 512 to the beam combiner / splitter 820, ..., the second optical signal S 12M The signal is transmitted through the first waveguide 51M to the beam combiner / splitter 8M0. In the lower transmitting assembly, the EC420 receives the first input optical signal S... 21 The beam is split into M second optical signals S 221 S 222 ... S 22M The second optical signal S 221 The second optical signal S is transmitted through the first waveguide 521 to the beam combiner / splitter 810. 222 After being transmitted through the first waveguide 522 to the beam combiner / splitter 820, ..., the second optical signal S 22M The signal is transmitted through the first waveguide 52M to the beam combiner / splitter 8M0.

[0216] Furthermore, the beam combiner / splitter 810 takes the two incoming second optical signals S 121 and S 221 The light is split into two transmission signals, which are then output through its two output terminals, allowing these two transmission signals to be transmitted to the two transmitter terminals b of the chip. 11 b 12 The beam combiner / splitter 820 receives two second optical signals S from the input. 122 and S 222 The light is split into two transmission signals, which are then output through its two output terminals, allowing these two transmission signals to be transmitted to the two transmitter terminals b of the chip. 21 b 22 ...The beam combiner / splitter 8M0 receives two second optical signals S from the input... 12M and S 22M The light is split into two transmission signals, which are then output through its two output terminals, allowing these two transmission signals to be transmitted to the two transmitter terminals b of the chip. M1 b M2Based on this, a total of 2M transmission signals will be emitted from the chip's 2M transmitters and enter the scanning component. These 2M transmission signals are then scanned by the scanning component into the detection space to measure targets within that space. For example, the 2M transmission signals correspond to 2M detection channels, and the 2M transmission signals are scanned into 2M areas. Thus, a single scan can detect 2M areas, increasing the scanning range and the number of detection channels, which contributes to increasing the point frequency.

[0217] In one example, each beam combiner / splitter is a power-type beam combiner / splitter. Each beam combiner / splitter mixes components of the two input second optical signals, for example, mixing 50% of each component to obtain two transmitted signals, and then outputs two transmitted signals. Based on this method, each pair of transmitted signals will have the same optical power, and these two transmitted signals can reach the same distance in different directions, making the ranging capability identical in different directions.

[0218] In one example, two first optical signals S from two transmitting components 11 S 21 They have different wavelengths, therefore, from the first optical signal S 11 The M second optical signals S are separated from the light 121 ~S 12M and from the first optical signal S 21 The M second optical signals S split from the middle 221 ~S 22M Therefore, they have different wavelengths. Each beam combiner / splitter receives two input signals of different wavelengths. After processing the two input signals of different wavelengths, each beam combiner / splitter obtains two dual-wavelength transmission signals and outputs them. Therefore, each transmission signal is a dual-wavelength signal. Although the ranging capability of each transmission signal is the same, it has two wavelengths, which can obtain a higher point frequency.

[0219] Or, in another example, two first optical signals S in two transmitting components 11 S 21 They have the same wavelength but different 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-light21 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.

[0220] 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.

[0221] 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.

[0222] Optionally, in the example of Figure 13, the target detection is combined by generating 2M dual-wavelength transmit signals using M beam combiners / splitters; this is just one possible implementation. In another implementation, one or more beam combiners / splitters can also split the transmit signals into three or more beams. In this case, the chip includes more than 2M transmitters. Alternatively, in yet another implementation, the M beam combiners can be replaced with M beam combiners, each combining two received input signals into a single transmit signal. In this case, the chip only needs M transmitters, each of which emits a dual-wavelength optical signal. Alternatively, in another implementation, one or more second optical signals output by EC410 and / or EC420 can be directly used as one or more single-wavelength transmission signals. Other second optical signals output by EC410 and / or EC420 can be combined or split using a beam combiner or beam splitter to produce one or more single-wavelength or dual-wavelength transmission signals. These single-wavelength and dual-wavelength transmission signals can then be used together to detect the target. Many other possible implementations exist, and they will not be listed here.

[0223] Optionally, as shown in Figure 13, 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.

[0224] In addition, there may be one or more receiving components, and the local oscillator signal of each receiving component can be separated from the input signal, transmitted signal or output signal of any device in EC (i.e. EC410 and EC420), first waveguide (i.e. M first waveguides 511 to 51M and M first waveguides 521 to 52M), beam combiner / splitter (i.e. M beam combiners / splitters 810 to 8M0) or waveguides after beam combiners / splitters.

[0225] For ease of understanding, four possible examples are given below.

[0226] Example 1, please refer to Figure 14a, which shows a possible structural diagram of the local oscillator signal being separated from the signal transmitted by the beam combiner / splitter 8M0. In this structure, there is only one receiving component, called receiving component 610. The beam combiner / splitter 8M0 also has a third output terminal. One input terminal of receiving component 610 is connected to the receiving terminal c of the chip, and the other input terminal is connected to the third output terminal of the beam combiner / splitter 8M0. The beam combiner / splitter 8M0 receives two second optical signals S. 12M S 22M Then, for the two second optical signals S 12M S 22M The components are mixed to obtain two transmitted signals and a local oscillator signal S3. The local oscillator signal S3 is output through the third output terminal and enters the receiving component 610, while the two transmitted signals are transmitted to the two transmitting terminals b. M1 and b M2 And it was launched into the exploration space.

[0227] Optionally, in the two second optical signals S 12M S 22M When the wavelengths are different, the two second optical signals S are mixed. 12M S 22MThe local oscillator signal S3 obtained from the components is also dual-wavelength. The receiving component 610 can mix the signals of these two wavelengths in the echo signal and the signals of these two wavelengths in the local oscillator signal S3 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 treated as noise signals and are not used.

[0228] Optionally, the optical power of the local oscillator signal S3 is less than the optical power of any of the transmitted signals output by the beam combiner / splitter 8M0. For example, the beam combiner / splitter 8M0 separates a lower-power optical signal from the synthesized dual-wavelength optical signal and outputs it from its third output terminal, while the remaining high-power optical signal is output from its first two output terminals through power equalization. In this case, it can be guaranteed that the optical power of the two transmitted signals output by the beam combiner / splitter 8M0 is the same. If EC410 and EC420 also have equally power-divided optical signals, then the optical power of the two transmitted signals output by the beam combiner / splitter 8M0 will be different from the optical power of the other transmitted signals; specifically, it will be less than the optical power of the other transmitted signals.

[0229] Example 2, please refer to Figure 14b, which shows a possible structural diagram of the local oscillator signal being separated from the input signals of EC410 and EC420. In this structure, there are two receiving components, referred to as receiving component 610 and receiving component 620. Receiving component 610 corresponds to the transmitting component where EC410 is located, and receiving component 620 corresponds to the transmitting component where EC420 is located.

[0230] For the receiving component 610, EC410 also has a second output terminal a 13 One input terminal of the receiving component 610 is connected to the receiving terminal c1 of the chip, and the other input terminal is connected to the second output terminal a of the EC410. 13 Up. EC410 receives the first optical signal S. 11 Then, the first optical signal S 11 Coupled to its own M+1 output terminals a 121 ~a 12M a 13 Above, where M are first output terminals a 121 ~a 12M Output M second optical signals S 121 ~S 12M Second output terminal a 13 Output local oscillator signal S 13 Assume the first optical signal S 11 If it has a first wavelength, then the local oscillator signal S 13 It also has a first wavelength, and the receiving component 610 is located at the second output terminal a of EC410. 13 Received local oscillator signal S of the first wavelength 13And receive the echo signal S from the receiver C1 of the chip. 14 Using echo signal S 14 The signal of the first wavelength and the local oscillator signal S 13 The frequency is mixed to obtain the intermediate frequency signal of the first wavelength.

[0231] Similarly, for the receiver component 620, the EC420 also has a second output terminal a. 23 One input terminal of the receiving component 620 is connected to the receiving terminal c2 of the chip, and the other input terminal is connected to the second output terminal a of the EC420. 23 Up. EC420 receives the first optical signal S. 21 Then, the first optical signal S 21 Coupled to its own M+1 output terminals a 221 ~a 22M a 23 Above, where M are first output terminals a 221 ~a 22M Output M second optical signals S 221 ~S 22M Second output terminal a 23 Output local oscillator signal S 23 Assume the second optical signal S 21 If it has a second wavelength, then the local oscillator signal S 23 It also has a second wavelength, and the receiving component 620 is located at the second output terminal a of the EC420. 23 Received local oscillator signal S of the second wavelength 23 And receive the echo signal S from the receiver C2 of the chip. 24 Using echo signal S 24 The signal of the second wavelength and the local oscillator signal S 23 The signal is mixed to obtain the intermediate frequency signal of the second wavelength.

[0232] 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 other wavelengths are treated as noise signals and not used, in order to improve the quality of the intermediate frequency signal.

[0233] Optionally, for each EC, the optical power of the local oscillator signal it divides is less than the optical power of the second optical signal it divides. For example, EC410 divides the first optical signal S... 11 A relatively low-power optical signal is coupled to the second output terminal a. 13 The remaining high-power optical signal is coupled to the M first output terminals a through power sharing or uneven distribution. 121 ~a 12MUp. EC420 transmits the first optical signal S 21 A similarly low-power optical signal is coupled to the second output terminal a. 23 The remaining high-power optical signal is coupled to the M first output terminals a through power sharing or uneven distribution. 221 ~a 22M Furthermore, optionally, the M beam combiners 810 to 8M0 can be power-sharing devices, so that the two transmission signals emitted by the two transmitters connected to each beam combiner will be of equal power, and the light output from each pair of detection channels will be uniform.

[0234] Example 3, please refer to Figure 14c, which shows a possible structural diagram of the local oscillator signal being separated from the signals transmitted in the first waveguide 511 and the first waveguide 52M. In this structure, there are also two receiving components, referred to as receiving component 610 and receiving component 620. Receiving component 610 corresponds to the transmitting component where EC410 is located, and receiving component 620 corresponds to the transmitting component where EC420 is located.

[0235] For the receiving component 610, the waveguide structure 400 also includes a directional coupler 710. The directional coupler 710 is coupled between the first waveguide 511 and one input terminal of the receiving component 610, and the other input terminal of the receiving component 610 is connected to the receiving terminal c1 of the chip. The directional coupler 710 does not contact the first waveguide 511, but is relatively close to it; therefore, it can transmit the second optical signal S from the first waveguide 511. 121 The local oscillator signal S is coupled out from the middle. 13 and the local oscillator signal S 13 The output is sent to the receiving component 610. Assume the first optical signal S... 11 Having a first wavelength, the second optical signal S 121 It also has a first wavelength, and the receiving component 610 receives the second optical signal S through the directional coupler 710. 121 The first wavelength local oscillator signal S is coupled out from the middle. 13 And receive the echo signal S from the receiver C1 of the chip. 14 Using echo signal S 14 The signal of the first wavelength and the local oscillator signal S 13 The frequency is mixed to obtain the intermediate frequency signal of the first wavelength.

[0236] Similarly, for the receiving component 620, the waveguide structure 400 also includes a directional coupler 720. The directional coupler 720 is coupled between the second waveguide 52M and one input terminal of the receiving component 620, and the other input terminal of the receiving component 620 is connected to the receiving terminal c2 of the chip. The directional coupler 720 does not contact the second waveguide 52M, but is relatively close to it; therefore, it can transmit the second optical signal S from the second waveguide 52M.22M The local oscillator signal S is coupled out from the middle. 23 and the local oscillator signal S 23 The output is sent to the receiving component 620. Assume the first optical signal S... 21 If it has a second wavelength, then the second optical signal S 22M It also has a second wavelength, and the receiving component 620 receives the second optical signal S through the directional coupler 720. 22M The second wavelength local oscillator signal S is coupled out from the middle. 23 And receive the echo signal S from the receiver C2 of the chip. 24 Using echo signal S 24 The signal of the second wavelength and the local oscillator signal S 23 The signal is mixed to obtain the intermediate frequency signal of the second wavelength.

[0237] 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 beam combiner / splitter 810 is less than the second optical signal S output from the EC410 to the first waveguide 511. 121 The optical power of the optical signal entering the beam combiner / splitter 8M0 is less than the second optical signal S output from the EC420 to the second waveguide 52M. 22M The optical power.

[0238] 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 710 receives the second optical signal S... 121 The lower-power optical signal is split from the first optical signal and output to the receiving component 610, while the remaining high-power optical signal is output to the beam combiner / splitter 810. The directional coupler 720 receives the second optical signal S... 22M A lower-power optical signal is split off and output to the receiving component 620, while the remaining high-power optical signal is output to the beam combiner / splitter 8M0. In this way, the higher-power beam can be used as the transmitted signal to improve the target detection effect.

[0239] 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:

[0240] Example 4, as shown in Figure 14d, illustrates another possible structural diagram for separating the local oscillator signal from the signals transmitted in the first waveguide 511 and the second waveguide 52M. This structure differs from that in Example 3 in that the directional coupler 710 in Example 3 is replaced by the beam splitter 730 in Example 4, and the directional coupler 720 in Example 3 is replaced by the beam splitter 740 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.

[0241] For example, as shown in Figure 14d, the input terminal of beam splitter 730 is connected to the output terminal of the first waveguide 511, and the two output terminals are respectively connected to one input terminal of beam combiner / splitter 810 and one input terminal of receiver 610. Beam splitter 730 splits the second optical signal S output from the first waveguide 511 into two optical signals. 121 The spectral splitting consists of the measurement optical signal and the local oscillator signal S. 13 The measurement optical signal is output to the beam combiner / splitter 810 to participate in the target measurement, and the local oscillator signal S is output to the beam combiner / splitter 810. 13 The output is sent to the receiving component 610 to complete the connection with the echo signal S. 14 The mixing is performed. Similarly, the input of beam splitter 740 is connected to the output of the second waveguide 52M, and the two outputs are respectively connected to one input of beam combiner / splitter 8M0 and one input of receiver 620. Beam splitter 740 converts the second optical signal S output from the second waveguide 52M into a frequency-mixing signal. 22M The spectral splitting consists of the measurement optical signal and the local oscillator signal S. 23 The measurement optical signal is output to the beam combiner / splitter 8M0 to participate in the target measurement, and the local oscillator signal S is output to the beam combiner / splitter 8M0. 23 The output is sent to the receiving component 620 to complete the connection with the echo signal S. 24 Frequency mixing.

[0242] 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.

[0243] Optionally, the above receiving component can be any component or combination thereof capable of performing mixing. For example, taking the structure shown in Figure 14a as an example, please refer to Figure 15a, which shows a specific structural schematic diagram of a receiving component provided in Embodiment 2. Referring to Figures 14a and 15a, in this example, the receiving component 610 includes a beam splitter 611 and M mixers, namely mixers 6121, 6122, ..., 612M. The beam splitter 611 has one input terminal and M output terminals. The input terminal is the input terminal of the receiving component 610, used to acquire the local oscillator signal S3. The M output terminals are respectively connected to the M first input terminals of the M mixers 6121 to 612M. The M second input terminals of the M mixers 6121 to 612M are connected to the M receiving terminals c1, c2, ..., c1 of the chip. M Here, the connections between the various components can be achieved through waveguides, optical fibers, or other means that can transmit optical signals. Figure 15a shows a waveguide connection as an example.

[0244] Based on this structure and connection, the input of beam splitter 611 can receive a dual-wavelength local oscillator signal S3. Beam splitter 611 splits the dual-wavelength local oscillator signal S3 (e.g., equally distributed with equal power) into M dual-wavelength sub-local oscillator signals S. 31 S 32 ... S 3M And through its M output terminals, these M dual-wavelength sub-local oscillator signals S 31 ~S 3M The outputs are distributed to M mixers 6121 to 612M. These M mixers 6121 to 612M can also receive signals from the chip's M receivers c1 to c2. M Received M echo signals S 41 S 42 ... S 4M 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 M IF signals generated by the M mixers 6121 to 612M together achieve the target measurement.

[0245] Optionally, the M mixers 6121-612M, together with subsequent components, achieve target measurement. For example, as shown in Figures 14a and 15a, the receiving component 610 may further include a detection element 613. The detection element 613 is connected between the output terminals of the M mixers 6121-612M and the electrical output terminal (d) of the chip, and is used to perform photoelectric detection on the M intermediate frequency signals generated by the M mixers 6121-612M to obtain and output an electrical signal. 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.

[0246] The structure of the receiving component 610 shown in Figure 15a can be directly extrapolated to the receiving component 620. For example, referring to Figure 15b, and combining Figure 15a and Figure 14c above, the receiving component 610 includes a beam splitter 611 and M mixers 6121 to 612M. The input terminal of the beam splitter 611 is the input terminal of the receiving component 610, used to acquire the local oscillator signal S. 13 The M output terminals of beam splitter 611 are respectively connected to the M first input terminals of M mixers 6121 to 612M, and the M second input terminals of the M mixers 6121 to 612M are connected to the M receiving terminals c of the chip. 11 c 12 ... c 1M Similarly, the receiving component 620 includes a beam splitter 621 and M mixers, namely mixers 6221, 6222, ..., 622M. The input terminal of the beam splitter 621 is the input terminal of the receiving component 620, used to acquire the local oscillator signal S. 23 The four outputs of beam splitter 621 are respectively connected to the M first inputs of M mixers 6221 to 622M, and the M second inputs of the M mixers 6221 to 622M are connected to the other M receivers of the chip. 21 c 22 ... c 2M .

[0247] 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 610, the input terminal of the beam splitter 611 can receive the local oscillator signal S of the first wavelength. 13 The beam splitter 611 splits the local oscillator signal S of the first wavelength. 13 The light is split (e.g., evenly divided with equal power) into M sub-local oscillator signals S of the first wavelength. 131 S 132 ... S 13M And through its M output terminals, these M sub-local oscillator signals S of the first wavelength are... 131 ~S 13M The outputs are distributed to M mixers 6121 to 612M. These M mixers 6121 to 612M can also receive signals from the chip's M receivers c. 11 ~c 1M Received M echo signals S 141 S 142 ... S 14MEach 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 M mixers 6121 to 612M 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.

[0248] Similarly, suppose the first optical signal S 21 If the wavelength is the second wavelength, then in the receiving component 620, the input terminal of the beam splitter 621 can receive the local oscillator signal S of the second wavelength. 23 The beam splitter 621 splits the second wavelength local oscillator signal S 23 The light is split (e.g., evenly split with equal power) into M sub-local oscillator signals of the second wavelength S. 231 S 232 ... S 23M And through its M output terminals, these M second-wavelength sub-local oscillator signals S 231 ~S 23M The outputs are distributed to M mixers 6221 to 622M. These M mixers 6221 to 622M can also receive signals from the chip's additional M receivers. 21 ~c 2M Received M echo signals S 241 S 242 ... S 24M 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 M IF signals generated by the M mixers 6221 to 622M 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.

[0249] Optionally, the 2M mixers 6121-612M and 6221-622M can be combined with subsequent components to achieve target measurement. For example, as shown in Figure 15b, the waveguide structure can also include a detection element 630. The detection element 630 is connected between the output terminals of the 2M mixers 6121-612M and 6221-622M and the electrical output terminal (d) of the chip. It is used to perform photoelectric detection on the 2M intermediate frequency signals generated by the 2M mixers 6121-612M and 6221-622M, 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.

[0250] 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.

[0251] Implementation Plan 3: Includes N launching components.

[0252] Please refer to Figure 16, 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.

[0253] As shown in Figure 16, each of the N transmitting modules includes the EC and M first waveguides described above. For example, as shown in Figure 16, from top to bottom, the first transmitting module includes EC410 and M first waveguides 511-51M, the second transmitting module includes EC420 and M first waveguides 521-52M, ..., and the Nth transmitting module includes EC4N0 and M first waveguides 5N1-5NM. In this case, the waveguide structure 400 also includes M beam combiners / splitters 810-8M0. Each of the M beam combiners / splitters 810-8M0 has N input terminals and at least two output terminals. The figure shows an example with two output terminals. The N input terminals of beam combiner / splitter 810 are respectively connected to the output terminals of the N first waveguides 511, 521, ..., 5N1 in the N transmitting modules, and the two output terminals of beam combiner / splitter 810 are connected to the two transmitting terminals b of the chip. 11 b 12 The N input terminals of the beam combiner / splitter 820 are respectively connected to the output terminals of the other N first waveguides 512, 522, ..., 5N2 in the N transmitting components. The two output terminals of the beam combiner / splitter 820 are connected to the other two transmitting terminals b of the chip. 21 b 22 ...The N input terminals of the beam combiner / splitter 8M0 are respectively connected to the output terminals of the N first waveguides 51M, 52M, ..., 5NM in the N transmitting components. The two output terminals of the beam combiner / splitter 8M0 are connected to the two transmitting terminals b of the chip. M1 b M2 .

[0254] Optionally, the N first optical signals S received by the N transmitting modules 11 ~S N1These are different wavelengths. In each transmitting component, the EC splits the input single-wavelength first optical signal into M single-wavelength second optical signals. These M single-wavelength second optical signals are transmitted through M first waveguides to M combiners / splitters 810–8M0. Each of the M combiners / splitters 810–8M0 performs beam combining and splitting processing on the input N wavelengths of second optical signals, obtaining two transmitted signals, both of which are N-wavelength optical signals. The two N-wavelength transmitted signals are emitted from the two transmitting ends of the chip to the scanning component, which scans them into the detection space. The 2M transmitted signals emitted by the M combiners / splitters are used to jointly measure the target in the detection space.

[0255] Alternatively, the N first optical signals S received by the N transmitting modules 11 ~S N1 It could also be the same wavelength but with different polarization states, or the same wavelength and the same 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 polarization states, or some of the first optical signals are the same wavelength but with different polarization states, while other first optical signals have the same wavelength and the same polarization state but are distinguished by polarization elements, and so on. There are many possible implementation methods, and no specific limitations are made here.

[0256] Optionally, similar to embodiment two above, as shown in Figure 16, 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 an element in one of the N ECs (i.e., 410–41N), N×M first waveguides (i.e., 511–51M, 521–52M, …, 5N1–5NM), M beam combiners / splitters (i.e., 810–8M0), and the waveguides after the M beam combiners / splitters. For example:

[0257] In one example, Figure 17a shows a structural diagram of a receiving component in a waveguide structure 400. This diagram illustrates the separation of the local oscillator signal S3 from the signal transmitted by the beam combiner / splitter 8M0. Schemes for separation from other beam combiners / splitters can be deduced by analogy to this diagram. In this example, the beam combiner / splitter 8M0 also has a third output terminal connected to the receiving component 610. The beam combiner / splitter 8M0 can also separate an N-wavelength local oscillator signal S3 from a synthesized N-wavelength beam signal. This N-wavelength local oscillator signal S3 enters the receiving component 610 and is mixed with the echo signal S4 received at the chip's receiving terminal c across N wavelengths to obtain an intermediate frequency signal.

[0258] In another example, Figure 17b shows a structural diagram of waveguide structure 400 including N receiving components, with N local oscillator signals S 13S 23 ... S N3 Taking the input signals from EC410, EC420, ..., EC4N0 as an example. In this example, the N receiving components are receiving component 610, receiving component 620, ..., receiving component 6N0, and the N receiving components 610 to 6N0 correspond one-to-one with the N EC410 to EC4N0. Each EC among the N EC410 to 4N0 also has a second output terminal, which is connected to the corresponding receiving component. Each EC can also separate a single-wavelength local oscillator signal from the input single-wavelength first optical signal and transmit it to the connected receiving component. 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 EC410 to 4N0... 11 ~S N1 When there are N wavelengths, there are N local oscillator signals S 13 ~S N3 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 the signals of other wavelengths are treated as noise signals and are not used.

[0259] In another example, Figure 17c shows a different structural diagram of waveguide structure 400 including N receiving components 610 to 6N0, with N local oscillator signals S 13 S 23 ... S N3 Taking the separation of signals transmitted from any of the first waveguides after EC410 to EC4N0 as an example, the waveguide structure 400 also includes N beam splitting elements. The illustration shows N directional couplers 710, 720, ..., 7N0 as an example. These N directional couplers 710 to 7N0 correspond one-to-one with N receiving components 610 to 6N0. Each directional coupler can be coupled between any first 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 through the coupled first 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 signal. When the first optical signal S input to the N EC410 to 4N0... 11 ~S N1 With N wavelengths, N receiving components can mix to obtain the intermediate frequency signals corresponding to each of the N wavelengths.

[0260] 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.

[0261] 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.

[0262] 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 split from each first waveguide, resulting in M×N local oscillator signals, corresponding to M×N receiving components. Alternatively, local oscillator signals can be split from at least two first waveguides partially connected by ECs, forming any number of local oscillator signals greater than N but less than M×N, 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 splitting local oscillator signals. And so on, which will not be listed here.

[0263] The waveguide structures described above can be applied to chips, such as silicon photonic chips, specifically SOI silicon photonic chips.

[0264] Please refer to Figure 18a, which shows a possible structural schematic diagram of a silicon photonic chip provided in this application. The silicon photonic chip 1800 includes a waveguide structure, which can be any waveguide structure described above, such as the waveguide structure 400 in any of the figures in Figures 4 to 17c.

[0265] Optionally, when the silicon photonics chip 1800 is an SOI silicon photonics chip, as shown in Figure 18a, it may include a silicon substrate layer and a buried oxide layer stacked sequentially (e.g., stacked from bottom to top as shown in the figure), with the waveguide structure disposed on the buried oxide layer. In some scenarios, the layer containing the waveguide structure may also be called a waveguide layer. The waveguide layer is a layer made of waveguide material. In this case, it can also be considered that the silicon photonics chip 1800 includes a silicon substrate layer, a buried oxide layer, and a waveguide layer stacked sequentially, with the waveguide structure located in the waveguide layer.

[0266] Alternatively, the area surrounding the waveguide structure, such as between multiple strip units, can be filled with a medium made of a low-refractive-index material. Here, "low-refractive-index" means less than the refractive index of the material used in the strip units. Several possible designs exist, such as:

[0267] Design 1, as shown in Figure 18a, involves a waveguide structure exposed to air. Air is a low-refractive-index material, and the waveguide structure's direct contact with air is equivalent to filling a medium with a low-refractive-index material, only the medium is air. This design can reduce the thickness of the silicon photonics chip 1800, saving the space occupied by the silicon photonics chip 1800.

[0268] Design 2, as shown in Figure 18b, further includes an upper cladding layer stacked on top of the buried oxide layer. The waveguide structure is embedded within the upper cladding layer, with its bottom contacting the buried oxide layer. The upper cladding layer can be made of any material with a refractive index lower than that of the waveguide structure, such as silicon oxide or silicon nitride. The upper cladding layer protects the internal waveguide structure.

[0269] The silicon photonics chip 1800 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.

[0270] Please refer to Figure 19, which shows a possible structural schematic diagram of a detection device provided in this application. The detection device 1900 may include the waveguide structure described above, or it may include the silicon photonic chip 1800 mentioned above, as shown in Figure 19.

[0271] Optionally, as shown in Figure 19, the detection device 1900 may further include a light source assembly 1910, 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 1800, transmitted through the emitting component on the waveguide structure, and then emitted from the emitting end of the silicon photonic chip 1800.

[0272] Optionally, as shown in Figure 19, the detection device 1900 further includes a scanning component 1920, which scans the light signal emitted from the emitter of the silicon photonic chip 1800 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 1920 to the receiver of the silicon photonic chip 1800. An echo signal generator (EC) can also be provided on the edge of the receiver of the silicon photonic chip 1800. The echo signal is coupled to the waveguide structure of the silicon photonic chip 1800 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 photonic chip 1800.

[0273] Further, optionally, as shown in FIG19, the detection device 1900 also includes a processing component 1931. The processing component 1931 is disposed on the electrical chip 1930. The input terminal of the electrical chip 1930 is connected between the electrical output terminal of the silicon photonic chip 1800 and the input terminal of the processing component 1931. Therefore, the electrical signal output by the electrical output terminal of the silicon photonic chip 1800 is transmitted to the processing component 1931. The processing component 1931 performs target detection based on the electrical signal, such as determining the distance and / or speed of the target.

[0274] Furthermore, alternatively, other components, such as an amplifier and an analog-to-digital converter (not shown), may also be included in the electrical chip 1930. The input of the amplifier is connected to the electrical output of the silicon photonics chip 1800, and the analog-to-digital converter is connected between the output of the amplifier and the input of the processing component 1931. The amplifier amplifies the electrical signal output by the silicon photonics chip 1800, and the analog-to-digital converter discretizes the amplified electrical signal, converts it into a digital signal, and outputs it to the processing component 1931, enabling the processing component 1931 to perform target detection based on the digital signal.

[0275] Optionally, as shown in Figure 19 above, the detection device 1900 may further include a window 1940, which is used to protect the various components inside the detection device 1900 and can transmit the light signal emitted by the detection device 1900.

[0276] It should be noted that the detection device architecture shown in Figure 19 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.

[0277] 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 20. This terminal device 2000 may include the silicon photonics chip described above, or it may include the detection device 1900 described above, as shown in Figure 20.

[0278] Optionally, as shown in Figure 20, the terminal device 2000 may further include a processor 2010, which is used to call programs or instructions to control the operation of the detection device 1900. Furthermore, the processor 2010 may also receive target-related information from the detection device 1900. When the terminal device 2000 is a vehicle, the processor 2010 may also perform vehicle path planning, braking, or starting based on the 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.

[0279] Furthermore, optionally, the terminal device 2000 may also include a memory 2020 for storing programs or instructions. Of course, the terminal device 2000 may also include other devices, such as wireless communication devices.

[0280] Processor 2010 may include one or more processing units. For example, processor 2010 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.

[0281] The memory 2020 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.

[0282] For example, the terminal device 2000 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.).

[0283] 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.

[0284] 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.

[0285] 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.

[0286] 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 inherent logic. Terms such as "first," "second," 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, the end-face coupler including an input terminal and M first output terminals, where M is an integer greater than or equal to 3; The input terminal of the end face coupler receives a first optical signal, and the M first output terminals of the end face coupler output M second optical signals, wherein the optical power of each of the M second optical signals is less than the optical power of the first optical signal.

2. The structure as described in claim 1, characterized in that, The input end of the end face coupler has a first mode size, and the M first output ends have M second mode sizes, wherein the first mode size is larger than each of the M second mode sizes.

3. The structure as described in claim 1 or 2, characterized in that, The waveguide structure also includes M first waveguides, which are connected to the M first output terminals.

4. The structure as described in claim 3, characterized in that, All M first waveguides are single-mode waveguides, and the mode size of all M first output terminals is the mode size of the single-mode waveguide.

5. The structure as described in any one of claims 1 to 4, characterized in that, The end-face coupler includes M strip-shaped units, each of the M strip-shaped units having a first end and a second end. The cross-sectional area of ​​the first end is less than a first preset value, and the cross-sectional area of ​​the second end is greater than a second preset value. The first preset value is less than or equal to the second preset value. The M first ends of the M strip-shaped units together serve as the input end of the end-face coupler, and the M second ends of the M strip-shaped units serve as the M first output ends of the end-face coupler.

6. The structure as described in claim 5, characterized in that, The M strip units are axially symmetric structures, and the spacing between adjacent strip units at the first end is less than a set spacing.

7. The structure as described in claim 5 or 6, characterized in that, The M strip units have the same cross-sectional area at their first ends, and the optical power of the second optical signal output by the strip units on both sides is less than the optical power of the second optical signal output by the strip unit in the middle.

8. The structure as described in claim 5 or 6, characterized in that, The cross-sectional area of ​​the strip units located on both sides at the first end is greater than that of the strip unit located in the middle at the first end, and the optical power of the second optical signal output by the strip units located on both sides is greater than or equal to the optical power of the second optical signal output by the strip unit located in the middle.

9. The structure as described in any one of claims 5 to 8, characterized in that, Some or all of the M strip units are subwavelength grating structures.

10. The structure as described in claim 9, characterized in that, All M strip units are subwavelength grating structures, and each M strip unit includes a periodic region; The M strip units constitute the subwavelength grating structure. The M strip units include a periodic region, a transition region, and a continuous region. The periodic region, the transition region, and the continuous region are arranged along the direction from the first end to the second end of the M strip units.

11. The structure as described in claim 10, characterized in that, The periodic region includes multiple short waveguide blocks, and the continuous region includes long waveguide blocks. The long waveguide blocks are connected to the middle portion of the multiple short waveguide blocks to form the transition region.

12. The structure according to any one of claims 1 to 11, characterized in that, The M first output terminals of the end face coupler are connected to the M transmitting terminals of the chip in which the waveguide structure is located. The M second optical signals serve as the M transmitting signals of the chip. The M transmitting signals are scanned to the detection space by the scanning component for the purpose of detecting the target.

13. The structure as described in claim 12, 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 the end-face coupler or any of the first waveguides.

14. The structure as described in claim 13, characterized in that, The end-face coupler also has a second output terminal, which outputs the local oscillator signal, and the receiving component is connected between the second output terminal and the receiving terminal of the chip.

15. The structure as described in claim 13, characterized in that, The waveguide structure further includes a beam splitter element, which is coupled between any of the first waveguides and the input end of the receiving component; The beam splitter is used to split the second optical signal transmitted through the coupled first waveguide into the local oscillator signal and output the local oscillator signal to the receiving component.

16. The structure as described in claim 15, characterized in that, The beam splitting element is a directional coupler or a beam splitter.

17. The structure according to any one of claims 1 to 11, characterized in that, The end-face coupler and the N first waveguides 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 M beam combiners and splitters, each of the M beam combiners and splitters having N input terminals and at least two first output terminals. The N input terminals are respectively connected to the output terminals of the N first waveguides in the N transmitting components, and the at least two first output terminals are connected to at least two transmitting terminals of the chip in which the waveguide structure is located. Each beam combiner / splitter is used to perform beam combining / splitting processing on the N incoming optical signals to obtain at least two transmitted signals; All the transmitted signals split by the M beam combiners and splitters are scanned into the detection space by the scanning component for target detection.

18. The structure as described in claim 17, characterized in that, The optical signals from the N emitting components have different wavelengths and / or different polarization states.

19. The structure as described in claim 17 or 18, 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 transmitting component's end-face coupler, any transmitting component's first waveguide, or any beam combiner / splitter.

20. The structure as described in claim 19, 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 second output terminal, which outputs the local oscillator signal. Each receiving component is connected between the second output terminal of the end-face coupler in the corresponding transmitting component and a receiving terminal of the chip.

21. The structure as described in claim 19, characterized in that, The M beam combiners and splitters include a first beam combiner and splitter, which also has a second output terminal. The receiving component is connected between the second output terminal and the receiving terminal of the chip. The first 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 second output terminal.

22. The structure as described in claim 19, 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 a first waveguide of the corresponding transmitting component and the input end of the corresponding receiving component. The N beam splitting elements are used to split the local oscillator signal from the optical signal transmitted through the coupled first waveguide, and output the local oscillator signal to the coupled receiving component.

23. The structure according to any one of claims 13 to 16, 19 to 22, characterized in that, The optical power of the local oscillator signal is less than the optical power of each of the M second optical signals.

24. The structure according to any one of claims 13 to 16, 19 to 23, characterized in that, The receiving component includes a beam splitter and M mixers. The input of the beam splitter is used to receive the local oscillator signal. The M outputs of the beam splitter are connected to the M first inputs of the M mixers. The M second inputs of the M mixers are connected to the M receiving terminals of the chip. The beam splitter is used to split the local oscillator signal into M sub-local oscillator signals and output the M sub-local oscillator signals to the M mixers; The M mixers are used to perform a mixing operation on the M sub-local oscillator signals and the M echo signals received by the M receivers of the chip to obtain M intermediate frequency signals.

25. The structure as described in claim 24, characterized in that, The receiving component further includes a detection element connected between the output terminals of the M mixers and the electrical output terminal of the chip; The detection element is used to perform photoelectric detection on the M intermediate frequency signals, obtain electrical signals, and output them.

26. A silicon photonic chip, characterized in that, Includes the waveguide structure as described in any one of claims 1 to 25.

27. The silicon photonic chip as described in claim 26, characterized in that, The silicon photonic chip comprises a silicon substrate layer, a buried oxide layer, and a waveguide layer stacked sequentially, with the waveguide structure located in the waveguide layer.

28. The silicon photonics chip as described in claim 27, characterized in that, The waveguide structure is exposed to air, or the silicon photonic chip further includes an upper cladding layer, which is stacked on the waveguide layer, and the waveguide structure is embedded in the upper cladding layer; wherein the refractive index of air or the refractive index of the material of the upper cladding layer is lower than the refractive index of the material of the waveguide structure.

29. A detection device, characterized in that, Including the silicon photonics chip as described in any one of claims 26 to 28.

30. The detection device as described in claim 29, 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.

31. The detection device as described in claim 29 or 30, 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.

32. The detection device as described in any one of claims 29 to 31, 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.

33. A terminal device, characterized in that, Includes the detection device as described in any one of claims 29 to 32.

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