A signal processing device, a detection device and a terminal device

Abstract

The application relates to a signal processing device, a detection device and a terminal equipment, and relates to the technical field of detection. The signal processing device comprises a light source, a first light splitting element, a second light splitting element, at least two optical delay lines and a frequency mixer. The at least two optical delay lines are waveguide delay lines integrated on a chip. The light signal output by the light source enters the first light splitting element to obtain a calibration local oscillator signal and a first to-be-delayed signal. The calibration local oscillator signal enters the frequency mixer, and the first to-be-delayed signal enters the second light splitting element. The at least two second to-be-delayed signals after passing through the second light splitting element enter the at least two optical delay lines respectively to obtain at least two delayed signals, and the at least two delayed signals enter the frequency mixer. In this way, when some optical delay lines are unavailable, the modulation signal can still be calibrated by using another part of the optical delay lines. Since the yield and reliability of the chip are guaranteed, the yield and reliability of the signal processing device can be improved.

Description

Technical Field

[0001] This application relates to the field of detection technology, and in particular to a signal processing device, a detection device, and a terminal device. Background Technology

[0002] Frequency-modulated continuous wave (FMCW) is a commonly used technique in LiDAR (Light Detection and Ranging) systems for measuring distance and velocity. It achieves distance and velocity detection by directly changing the frequency of the laser's emitted light source. During frequency modulation, due to the influence of the laser's internal physical mechanisms (such as manufacturing imperfections and thermal effects), the frequency of the input modulation signal and the emitted laser beam may become nonlinear. This results in a nonlinear change in the frequency of the emitted laser beam over time, known as frequency modulation nonlinearity.

[0003] Frequency modulation nonlinearity can affect the measurement accuracy of FMCW LiDAR. To address this issue, the modulation signal input to the laser needs to be calibrated. Currently, mainstream calibration schemes typically use an asymmetric Mach-Zehnder interferometer (AMZI) structure based on an on-chip integrated optical delay line. However, on-chip integrated optical delay lines may become unusable or fail to meet standards due to manufacturing processes, aging, or other factors. This reduces the accuracy of modulated signal calibration, or even prevents calibration altogether. Consequently, the chip integrating this optical delay line becomes unusable, resulting in low yield and poor reliability.

[0004] In summary, improving the lifespan of chips is a pressing technical problem that needs to be solved in the field of FMCW LiDAR. Summary of the Invention

[0005] This application provides a signal processing device, a detection device, and a terminal device to increase the yield and reliability of chips.

[0006] In a first aspect, this application provides a signal processing apparatus, including a light source, a first beam splitter, a second beam splitter, at least two optical delay lines, and a mixer; wherein, the at least two optical delay lines are waveguide delay lines integrated on a chip, and the at least two optical delay lines are disposed one-to-one on at least two waveguide layers of the chip; the optical signal output from the light source enters the first beam splitter to obtain a calibration path local oscillator signal and a first delay signal, the calibration path local oscillator signal enters the mixer, and the first delay signal enters the second beam splitter; the at least two delay signals after passing through the second beam splitter respectively enter the at least two optical delay lines to obtain at least two delay signals, and the at least two delay signals enter the mixer.

[0007] Based on the above structure, by increasing the number of optical delay lines, even if some optical delay lines become unusable, the remaining optical delay lines can still be used to calibrate and modulate the signal, thus ensuring chip yield and reliability. Because chip yield and reliability are guaranteed, the yield and reliability of the signal processing device can be increased, while avoiding frequent chip replacements.

[0008] It should be noted that the original structure of the chip includes at least two waveguide layers. This application utilizes the original structure of the chip to increase the number of optical delay lines, which does not burden the chip structure or require any changes to the original structure. Furthermore, each waveguide layer has only one optical delay line, which avoids the situation where all optical delay lines in the same waveguide layer become unusable simultaneously due to identical manufacturing processes.

[0009] In one possible design, the signal processing device further includes an interlayer coupler disposed on any one of at least two waveguide layers of the chip, with the second beam splitter and the input terminal of the interlayer coupler disposed on the same waveguide layer; based on this, the interlayer coupler connects the second beam splitter to at least two optical delay lines, except for the optical delay lines disposed on the same waveguide layer as the second beam splitter; the interlayer coupler is used to input the second delay signal corresponding to the other optical delay lines to the other optical delay lines respectively.

[0010] In this design, the output of the interlayer coupler is connected to the input of other optical delay lines except for the optical delay line disposed in the same waveguide layer as the second beam splitter. Among the at least two second delay signals after passing through the second beam splitter, the second delay signals corresponding to the other optical delay lines except for the optical delay lines in the same layer as the second beam splitter are respectively entered into at least two optical delay lines through the interlayer coupler.

[0011] In one possible design, the signal processing device further includes a photodetector, a processing element, and a driving circuit; wherein, the signal after being mixed by the mixer is detected by the photodetector and converted into an electrical signal, the electrical signal is processed by the processing element to obtain a feedback signal and input to the driving circuit, the feedback signal is used to adjust the modulation signal input to the light source by the driving circuit, thereby calibrating the linearity between the light signals output by the light source.

[0012] In one possible design, the signal processing device further includes an optical combiner connected between at least two optical delay lines and a mixer; the optical combiner is used to combine at least two delayed signals.

[0013] Based on this design, at least two delayed signals are combined into one beam using an optical beam combiner, so that the combined signals enter the mixer. The mixer mixes the combined signal with the calibration path local oscillator signal, thus eliminating the need for a separate mixer for each delayed signal and reducing the number of mixers required.

[0014] In one possible design, there are at least two mixers, each connected to at least two delay lines in a one-to-one correspondence; there are at least two processing elements, each connected to at least two mixers in a one-to-one correspondence.

[0015] Based on this design, at least two delayed signals are fed into at least two mixers, allowing each mixer to process one of the delayed signals in a one-to-one correspondence. The signals processed by the at least two mixers are then detected by a photodetector and converted into multiple electrical signals, which are then fed into the at least two processing elements respectively. Because each delayed signal is processed individually, the accuracy of the subsequent calibration modulation signal can be guaranteed.

[0016] In one possible design, the signal processing device further includes an amplifier and an analog-to-digital converter; wherein the amplifier and the analog-to-digital converter are connected between the photodetector and the processing element.

[0017] Based on this design, the amplifier is used to amplify the signal; the analog-to-digital converter (ADC) is used to convert the electrical signal from analog to digital to obtain a digital signal. Alternatively, the electrical signal is processed by the amplifier and then converted into a digital signal by the ADC; the digital signal is then processed by the processing unit to obtain a feedback signal.

[0018] In one possible design, the signal processing device further includes an electrical combiner connected between the photodetector and the processing element; at least two mixers are connected one-to-one with at least two delay lines; the electrical combiner is used to combine the signals processed by the at least two mixers.

[0019] Based on this design, at least two delayed signals are fed into at least two mixers. The signals processed by the mixers are detected by a photodetector and converted into multiple electrical signals. These multiple electrical signals are then combined by an electrical combiner, resulting in a single bundle. The bundled electrical signal then enters a processing element. Since a separate processing element is not required for each delayed signal, the number of processing elements is reduced.

[0020] In one possible design, the signal processing device further includes an amplifier and an analog-to-digital converter; wherein the amplifier and the analog-to-digital converter are connected between the electrical combiner and the processing element.

[0021] Optionally, the mixer is a 180° mixer or a 90° mixer.

[0022] In one possible design, any two of the at least two optical delay lines are made of different materials.

[0023] This design allows for different signal delays, improving accuracy during subsequent calibration and modulation. It also prevents optical delay lines made of identical materials from all failing at the same time or within short intervals.

[0024] In one possible design, the mixer is a 180° mixer or a 90° mixer, which is used to mix the calibration path local oscillator signal and the signal after being delayed by the at least two optical delay lines.

[0025] Secondly, this application provides a detection device, including the signal processing device in the first aspect or any of the designs in the first aspect.

[0026] Thirdly, this application provides a terminal device that includes the signal processing device in the first aspect or any of the designs in the first aspect, or includes the detection device in the second aspect.

[0027] The technical effects that can be achieved by the second or third aspect 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

[0028] Figure 1 An illustrative diagram shows a possible application scenario to which this application applies;

[0029] Figure 2 An exemplary schematic diagram of a mainstream direct-modulation FMCW LiDAR architecture is shown below;

[0030] Figure 3 An exemplary schematic diagram of the structure of a directly modulated FMCW LiDAR laser provided in the industry is shown;

[0031] Figure 4 An exemplary schematic diagram of a chip system architecture provided in this application is shown;

[0032] Figure 5 An exemplary schematic diagram of a signal processing apparatus provided in Embodiment 1 is shown;

[0033] Figure 6 An exemplary schematic diagram of a signal processing apparatus provided in Embodiment 2 is shown;

[0034] Figure 7 An exemplary schematic diagram of a signal processing apparatus provided in Embodiment 3 is shown;

[0035] Figure 8 An exemplary schematic diagram of another signal processing apparatus provided in Embodiment 1 is shown;

[0036] Figure 9 An exemplary schematic diagram of another signal processing device provided in Embodiment 1 is shown;

[0037] Figure 10 An exemplary schematic diagram of another signal processing device provided in Embodiment 2 is shown;

[0038] Figure 11 An exemplary schematic diagram of another signal processing device provided in Embodiment 2 is shown;

[0039] Figure 12 An exemplary schematic diagram of another signal processing apparatus provided in Embodiment 3 is shown;

[0040] Figure 13 An exemplary schematic diagram of another signal processing device provided in Embodiment 3 is shown;

[0041] Figure 14 An exemplary schematic diagram of a detection device provided in this application is shown;

[0042] Figure 15 An exemplary schematic diagram of a terminal device provided in this application is shown. Detailed Implementation

[0043] The embodiments of this application will now be described in detail with reference to the accompanying drawings.

[0044] The following describes the possible application scenarios of this application.

[0045] In one possible implementation, the signal processing device provided in this application can be integrated into the detection device, which can be installed on a vehicle, including but not limited to: vehicles, ships, airplanes, drones, trains, subways, automated guided vehicles (AGVs), or unmanned vehicles. For an example, please refer to [link to example]. Figure 1 This diagram illustrates one possible application scenario of this application. Taking the detection device installed on the front bumper of a vehicle as an example, this 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, rearview mirrors, near the doors, 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 stone collision is lower, it does not affect the vehicle's appearance, and the windshield itself has built-in window heating and defogging functions as well as wiper cleaning functions.

[0046] 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 of terminal devices, such as smartphones, smart home devices, smart manufacturing equipment, medical devices, industrial equipment, and robots. These will not be listed exhaustively here.

[0047] It should be noted that the application scenarios described in this application are for the purpose of more clearly illustrating the technical solutions of this application, and do not constitute a limitation on the technical solutions provided in this application.

[0048] 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.

[0049] The detection devices mentioned above may include, but are not limited to, LiDAR, such as a direct-modulation FMCW LiDAR, or simply a direct-modulation FMCW LiDAR. Before introducing the specific solution provided in this application, the relevant content of direct-modulation FMCW LiDAR will be introduced below. It should be noted that this content is for the convenience of those skilled in the art and does not constitute a limitation on the scope of protection claimed in this application.

[0050] Frequency-modulated continuous wave (FMCW) is a laser technology commonly used to measure distance and velocity. Based on the principle of frequency-modulated continuous wave, it calculates distance by applying a modulation signal to a laser beam and measuring the frequency difference between the reflected echo signal (received signal) and the transmitted signal (detected signal). FMCW also utilizes the Doppler effect to calculate the velocity of the object being measured.

[0051] Furthermore, in FMCW LiDAR, the probe signal is typically a linear frequency modulated (LFM) signal. After this LFM signal interacts with the object under test, the reflected echo signal will also exhibit the same frequency variation characteristics. Depending on the distance to the object, 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 difference between the probe signal and the echo signal is calculated to obtain a low-frequency beat signal, also known as a beat frequency signal or intermediate frequency (IF) signal. The IF signal contains information about the frequency difference between the two signals, and this frequency difference is proportional to the target distance. This means that the distance from the emitting source of the probe signal to the object under test can be calculated using the frequency difference.

[0052] However, during frequency modulation, physical mechanisms (such as imperfections in manufacturing processes and thermal effects) can cause the modulation signal to exhibit nonlinearity, leading to frequency modulation nonlinearity. This phenomenon affects the measurement accuracy of FMCW LiDAR. To address this issue, the modulation signal needs to be calibrated. Currently, mainstream calibration schemes typically use an asymmetric mach-zehnder interferometer (AMZI) structure based on an on-chip integrated optical delay line.

[0053] like Figure 2The diagram illustrates the architecture of a mainstream direct-modulation FMCW LiDAR. This direct-modulation FMCW LiDAR includes a light source, a beam splitter, a target measurement path, a reference calibration path, and a driving circuit. The reference calibration path is connected to one output terminal of the beam splitter, and the target measurement path is connected to the other output terminal. During operation, the driving circuit generates a modulation signal (L1) and inputs it to the light source. This modulation signal L1 drives the light source to emit a light signal S whose frequency changes linearly with time. The beam splitter separates the light signal S into a probe signal and a calibration signal. The probe signal is output to the target measurement path, and the calibration signal is output to the reference calibration path.

[0054] The target measurement path measures the target based on the detection signal to obtain information such as the target's distance and velocity. The reference calibration path generates a feedback signal (P) based on the calibration signal and outputs the feedback signal P to the drive circuit. The drive circuit adjusts the output modulation signal L1 based on the feedback signal P to make the frequency change of the light signal S emitted by the light source linear, that is, the light signal S emitted by the light source changes linearly with time.

[0055] For example, taking a laser as the light source and beam splitter 1 as the beam splitter element, please refer to [link to relevant documentation]. Figure 3 This diagram illustrates the specific structure of a directly modulated FMCW LiDAR laser. In this example, the reference calibration path may include a beam splitter 2, an optical delay line, a mixer, a photodetector, and a processing element. The laser emits a laser beam S based on the modulation signal L1 input to the drive circuit. The beam splitter 1 splits the laser beam S into a probe signal and a calibration signal. The probe signal is input to the target measurement path for target measurement, and the calibration signal is input to the beam splitter 2. The beam splitter 2 splits the calibration signal into a signal light to be delayed and a local oscillator light from the calibration path. The local oscillator light from the calibration path is directly input to the mixer, while the signal light to be delayed is also input to the mixer after being delayed by the optical delay line. The mixer mixes the local oscillator light from the calibration path and the delayed signal light to obtain an intermediate frequency (IF) signal. The photodetector (which converts the optical signal into an electrical signal) detects this IF signal and inputs the detected IF signal to the processing element. The processing element processes the IF signal to obtain a feedback signal P, which is then input to the drive circuit. The driving circuit adjusts the modulation signal L1 output to the laser based on the input feedback signal P.

[0056] In the above examples, the structure of the target measurement path includes, but is not limited to, the following optoelectronic devices: beam splitter, circulator, mixer, balanced photodetector (BPD), trans-impedance amplifier (TIA), analog-to-digital converter (ADC), and digital signal processing unit (DSP). Since optical delay lines generally only exist in the reference calibration path, this application mainly improves the reference calibration path and does not limit the electronic components included in the target measurement path. For ease of description, this application uses the term "target measurement path" generally and does not limit its specific structure.

[0057] Optical delay lines are typically integrated into chips. When an optical delay line fails due to manufacturing processes, aging, or other reasons, the signal light cannot be delayed, making it impossible to calibrate the modulated signal. Consequently, the calibration of the modulated signal fails to meet requirements (i.e., the aforementioned reference calibration path becomes unusable). In other words, when an optical delay line fails, the chip integrating it becomes unusable, resulting in low chip yield and poor reliability.

[0058] In view of this, this application provides a signal processing device that integrates at least two optical delay lines on a chip, so that when some optical delay lines among multiple optical delay lines become unavailable, the other part of the optical delay lines can still be used to calibrate and modulate the signal, thereby increasing the yield and reliability of the chip.

[0059] Please see Figure 4 This diagram illustrates a system architecture of a chip provided in this application, which is disposed in a signal processing device. The chip includes at least two waveguide layers (semiconductor process) and a substrate layer (including but not limited to a buried oxide layer and a silicon substrate layer). For ease of description, Figure 4 Two waveguide layers, waveguide layer 1 and waveguide layer 2, are shown as an example only. At least two optical delay lines are integrated in these waveguide layers. Optionally, the number of optical delay lines is the same as the number of waveguide layers, or the number of optical delay lines is greater than the number of waveguide layers, or the number of optical delay lines is less than the number of waveguide layers. Because different optical delay lines in the same waveguide layer may fail simultaneously due to identical manufacturing processes, it is preferable that at least two optical delay lines are disposed one-to-one in at least two waveguide layers of the chip, i.e., each waveguide layer integrates one optical delay line (in this case, the number of optical delay lines is the same as the number of waveguide layers). Figure 4As shown, optical delay line 1 is disposed on waveguide layer 1, and optical delay line 2 is disposed on waveguide layer 2. This avoids the situation where all optical delay lines become unusable simultaneously due to identical fabrication processes within the same waveguide layer. Optionally, when the number of optical delay lines is greater than the number of waveguide layers, multiple optical delay lines can be disposed in one waveguide layer; when the number of optical delay lines is less than the number of waveguide layers, the optical delay lines can be disposed in some of the waveguide layers.

[0060] In this application, the signals entering at least two optical delay lines are transmitted by a beam splitter (referred to as a second beam splitter for ease of distinction). Therefore, the second beam splitter needs to be connected to at least two optical delay lines. Optionally, the second beam splitter is directly connected to the at least two optical delay lines, or the second beam splitter is connected via an interlayer coupler. The interlayer coupler is used to input signals to optical delay lines in different waveguide layers. Figure 4 As shown, the signal processing device includes an interlayer coupler, which can be disposed in any one of at least two waveguide layers of the chip. Figure 4 For example, the second beam splitter is typically located in the same waveguide layer as the input of the interlayer coupler (e.g., in waveguide layer 1). Since the optical delay line (e.g., in waveguide layer 1) is located in the same waveguide layer as the second beam splitter... Figure 4 The optical delay line 1 in the middle can be directly connected to the second beam splitter. Therefore, the interlayer coupler is connected between the second beam splitter and at least two optical delay lines, except for the optical delay line that is disposed in the same waveguide layer as the second beam splitter (such as the optical delay line 1 in the middle). Figure 4 The output terminals of the interlayer coupler are connected to the input terminals of optical delay lines (2) in the waveguide layer, except for the optical delay line that is located in the same waveguide layer as the second beam splitter. The multiple output terminals of the interlayer coupler (each corresponding to one of the other optical delay lines) are respectively located in the same waveguide layer as their corresponding optical delay lines.

[0061] by Figure 4 For example, one output terminal of the second beam splitter is connected to the input terminal of optical delay line 1, and the other output terminal of the second beam splitter is connected to the input terminal of the interlayer coupler. The output terminal of the interlayer coupler is connected to the input terminal of optical delay line 2 (i.e., other optical delay lines). In this way, the interlayer coupler can input the signal output by the second beam splitter into other optical delay lines.

[0062] It should be noted that the aforementioned beam splitting element and interlayer coupler can be integrated into the chip or disposed outside the chip, and this application does not impose any restrictions on this.

[0063] In order to calibrate the modulated signal, the signal processing device, in addition to the chip, at least two optical delay lines, a second beam splitter, and an interlayer coupler described above, also needs to include a light source, a first beam splitter, a mixer, and other optoelectronic devices. Some of these optoelectronic devices can be integrated onto the chip, similar to optical delay lines, such as the second beam splitter and the mixer, which are integrated onto the aforementioned chip; this application does not impose any limitations on this. The following is a description of the appendix... Figure 5 To be continued Figure 13 This application provides a detailed description of the signal processing apparatus proposed in this application.

[0064] It should be noted that in the accompanying drawings of this application, two devices are connected by a "dashed line," indicating that the two devices are connected through an optical medium, such as an optical fiber, waveguide, or any medium capable of transmitting optical signals. In short, two devices connected by a "dashed line" can transmit optical signals. Similarly, two devices are connected by a "solid line," indicating that the two devices are connected through an electrical medium (also called an electrical connection), such as a cable, wire, or any medium capable of transmitting electrical signals. In short, two devices connected by a "solid line" can transmit electrical signals. Furthermore, the connection of the interlayer coupler has been described above, and the connection relationship between the second beam splitter and at least two optical delay lines will not be repeated below.

[0065] Based on the method of generating feedback signal (P), the embodiments of this application provide the following implementation schemes. It should be understood that the following implementation schemes are merely examples, and this application does not impose any specific limitations on them.

[0066] Implementation Plan 1: The signal processing device includes a light source, a first beam splitter, a second beam splitter, and a third beam splitter. Components, at least two optical delay lines (number of which is n, where n is an integer greater than 1), optical combiner, mixer, photodetector, amplifier Devices, analog-to-digital converters, processing components, and drive circuits.

[0067] Please see Figure 5This diagram illustrates the structure of a signal processing device provided in this application. The connection relationships of the various optoelectronic devices in this structure are as follows: the input terminal of the light source is connected to the driving circuit; the output terminal of the light source is connected to the input terminal of the third beam splitter; the output terminal of the third beam splitter is connected to both the target measurement path and the input terminal of the first beam splitter; the output terminal of the first beam splitter is connected to both the input terminal of the mixer and the input terminal of the second beam splitter; the output terminal of the second beam splitter is connected to the input terminals of at least two optical delay lines; the output terminals of the at least two optical delay lines are connected to the input terminal of the optical combiner; the output terminal of the optical combiner is connected to the input terminal of the mixer; the output terminal of the mixer is connected to the input terminal of the photodetector; the output terminal of the photodetector is connected to the input terminal of the amplifier; the output terminal of the amplifier is connected to the input terminal of the analog-to-digital converter; the output terminal of the analog-to-digital converter is connected to the input terminal of the processing element; and the output terminal of the processing element is connected to the driving circuit. The first beam splitter, the second beam splitter, the at least two optical delay lines, the optical combiner, the mixer, the photodetector, the amplifier, the analog-to-digital converter, and the processing element together form a reference calibration path. It should be noted that the number of input and output terminals of any optoelectronic device is related to the number of input and output signals. For example, the number of output terminals of the second beam splitter is the same as the number of two optical delay lines. This application does not impose any restrictions on this.

[0068] It can be seen that the signal transmission between the various optoelectronic devices inside the signal processing device forms a loop. For example... Figure 5 As shown, the signal transmission process of this circuit is as follows: the optical signal S output by the light source enters the first beam splitter after passing through the calibration signal output by the third beam splitter, resulting in the calibration path local oscillator signal (or calibration path local oscillator light) and the first delay signal S1. The calibration path local oscillator signal directly enters the mixer, while the first delay signal S1 enters the second beam splitter. The second beam splitter splits the first delay signal S1 to obtain at least two second delay signals (corresponding one-to-one with at least two optical delay lines, S21, S22, ..., S2n), which then enter at least two optical delay lines respectively. That is, after passing through the second beam splitter, at least two second delay signals enter at least two optical delay lines respectively. It can be understood that after at least two second delay signals are delayed by at least two optical delay lines, at least two delayed signals (S21', S22', ..., S2n') can be obtained. These delayed signals enter the optical combiner, which then combines these delayed signals to obtain the combined delayed signal S1'. The delayed signal S1' then enters the mixer, which mixes the received delayed signal and the calibration path local oscillator signal to obtain the intermediate frequency signal Z.

[0069] Based on the above scheme, the achieved technical effects are as follows: When some optical delay lines integrated on the chip inside the signal processing device become unavailable, the remaining optical delay lines can still be used to calibrate and modulate the signal, thereby increasing the chip yield and reliability. Since the chip yield and reliability are guaranteed, the yield and reliability of the signal processing device can be increased, while also avoiding frequent chip replacements. Furthermore, at least two delayed signals are combined into one beam using an optical combiner, so that the combined signals enter the mixer. This eliminates the need for a separate mixer for each delayed signal, thus reducing the number of mixers required.

[0070] The signal after mixing (i.e., the intermediate frequency signal Z) is detected by the photodetector and converted into an electrical signal, which is then output to an amplifier or an analog-to-digital converter. It is understood that the amplifier and analog-to-digital converter are used to process the electrical signal (e.g., the amplifier amplifies the signal, and the analog-to-digital converter converts the electrical signal into a digital signal). This application does not restrict the order of the amplifier and analog-to-digital converter. This application exemplarily places the amplifier before the analog-to-digital converter.

[0071] The signal processed by the analog-to-digital converter (here referred to as the digital signal for clarity) enters the processing element, which then sends a feedback signal P to the drive circuit based on the digital signal (obtained by processing the detected intermediate frequency signal Z). The drive circuit then adjusts the modulation signal L1 output to the light source according to the feedback signal P to calibrate the linearity of the light signal S output by the light source.

[0072] Implementation Scheme 2: The signal processing device includes a light source, a first beam splitter, a second beam splitter, and a third beam splitter. The components include at least two optical delay lines (two delay lines are provided here as an example for ease of description), and at least two mixers. (Corresponding one-to-one with at least two optical delay lines), at least two photodetectors, at least two amplifiers, at least two analog-to-digital converters Replacement components, at least two processing components, and a drive circuit. These include optical delay lines, mixers, photodetectors, amplifiers, and analog-to-digital converters. The conversion element and the processing element have a one-to-one correspondence.

[0073] Please see Figure 6This diagram illustrates the structure of a signal processing device provided in this application. The connection relationships of the various optoelectronic devices in this structure are as follows: the input terminal of the light source is connected to the driving circuit; the output terminal of the light source is connected to the input terminal of the third beam splitter; the output terminal of the third beam splitter is connected to both the target measurement path and the input terminal of the first beam splitter; the output terminal of the first beam splitter is connected to both the input terminal of the mixer and the input terminal of the second beam splitter; the output terminal of the second beam splitter is connected to the input terminals of at least two optical delay lines; the output terminals of the at least two optical delay lines are connected to the input terminals of their corresponding mixers; the output terminals of the mixers are connected to the input terminals of their corresponding photodetectors; the output terminals of the photodetectors are connected to the input terminals of their corresponding amplifiers; the output terminals of the amplifiers are connected to the input terminals of their corresponding analog-to-digital converters; the output terminals of the analog-to-digital converters are connected to the input terminals of their corresponding processing elements; and the output terminal of the processing element is connected to the driving circuit. The first beam splitter, the second beam splitter, at least two optical delay lines, at least two mixers, at least two photodetectors, at least two amplifiers, at least two analog-to-digital converters, and at least two processing elements together form a reference calibration path.

[0074] Referring to the first implementation scheme above, the signal transmission between the various optoelectronic devices inside the signal processing device forms a loop. For example... Figure 6 As shown, the signal transmission process of this circuit is as follows: the optical signal S output by the light source enters the first beam splitter after passing through the calibration signal output by the third beam splitter, resulting in the calibration path local oscillator signal (or calibration path local oscillator light) and the first delay signal S1. The calibration path local oscillator signal directly enters the mixer, while the first delay signal S1 enters the second beam splitter. The second beam splitter performs beam splitting on the first delay signal S1, obtaining at least two second delay signals (such as...). Figure 6 (S21, S22) and respectively enter at least two optical delay lines, that is, at least two second signals to be delayed after passing through the second beam splitter enter at least two optical delay lines respectively. It can be understood that after at least two second signals to be delayed are delayed by at least two optical delay lines, at least two delayed signals (such as...) can be obtained. Figure 6 (S21' and S22'). These delayed signals are respectively fed into the mixers corresponding to the optical delay lines. The mixers then perform frequency mixing on the received delayed signals and the calibration path local oscillator signals to obtain intermediate frequency (IF) signals. For example, one mixer mixes the received delayed signal S21' and the calibration path local oscillator signals to obtain IF signal Z1; another mixer mixes the received delayed signal S22' and the calibration path local oscillator signals to obtain IF signal Z2.

[0075] Based on the above scheme, in addition to the technical effects achieved by the first scheme, this scheme can process each delayed signal separately after the signal is processed by at least two mixers, so as to ensure the accuracy of the subsequent calibration modulation signal.

[0076] The signals processed by the mixer (such as the intermediate frequency signals Z1 and Z2 mentioned above) are detected by the corresponding photodetectors and converted into electrical signals, which are then output to the corresponding amplifiers and analog-to-digital converters. The digital signals processed by the analog-to-digital converters enter the processing element, which then sends a feedback signal P to the drive circuit based on the digital signals. The drive circuit then adjusts the modulation signal L1 output to the light source based on the feedback signal P to calibrate the linearity of the light signal S output by the light source. For example, the intermediate frequency signal Z1 processed by mixer 1 is detected by photodetector 1 and converted into an electrical signal, which is then output to amplifier 1 and analog-to-digital converter 1. The digital signals processed by analog-to-digital converter 1 enter the processing element 1, which then sends a feedback signal P1 to the drive circuit based on the digital signals. Similarly, the intermediate frequency signal Z2 processed by mixer 2 is detected by photodetector 2 and converted into an electrical signal, which is then output to amplifier 2 and analog-to-digital converter 2. The digital signals processed by analog-to-digital converter 2 enter the processing element 2, which then sends a feedback signal P2 to the drive circuit based on the digital signals. The advantage of doing this is that the drive circuit can adjust the modulation signal based on multiple feedback signals (such as adjusting the modulation signal by calculating the average value of multiple feedback signals or adjusting the modulation signal by selecting the feedback signal with the best signal quality) to ensure the accuracy of the calibration modulation signal.

[0077] Implementation Scheme 3: The signal processing device includes a light source, a first beam splitter, a second beam splitter, and a third beam splitter. The components include at least two optical delay lines (two delay lines are provided here as an example for ease of description), and at least two mixers. (Corresponding one-to-one with at least two optical delay lines), at least two optical detection elements, an electrical combiner, an amplifier, and an analog-to-digital converter. Processing components and driving circuits. Among them, optical delay lines, mixers, and photodetectors have a one-to-one correspondence.

[0078] Please see Figure 7This diagram illustrates the structure of a signal processing device provided in this application. The connection relationships of the various optoelectronic devices in this structure are as follows: the input terminal of the light source is connected to the driving circuit; the output terminal of the light source is connected to the input terminal of the third beam splitter; the output terminal of the third beam splitter is connected to both the target measurement path and the input terminal of the first beam splitter; the output terminal of the first beam splitter is connected to both the input terminal of the mixer and the input terminal of the second beam splitter; the output terminal of the second beam splitter is connected to the input terminals of at least two optical delay lines; the output terminals of the at least two optical delay lines are connected to the input terminals of their corresponding mixers; the output terminals of the mixers are connected to the input terminals of their corresponding photodetectors; the output terminals of the photodetectors are connected to the input terminals of the electrical combiner; the output terminals of the electrical combiner are connected to the input terminals of the amplifier; the output terminals of the amplifier are connected to the input terminals of the analog-to-digital converter; the output terminals of the analog-to-digital converter are connected to the input terminals of the processing element; and the output terminal of the processing element is connected to the driving circuit. The first beam splitter, the second beam splitter, at least two optical delay lines, at least two mixers, at least two photodetectors, the amplifier, the analog-to-digital converter, and the processing element together form a reference calibration path.

[0079] Referring to the second implementation scheme described above, the signal transmission between the various optoelectronic devices inside the signal processing device forms a loop. For example... Figure 7 As shown, the signal transmission process of this circuit is as follows: the optical signal S output by the light source enters the first beam splitter after passing through the calibration signal output by the third beam splitter, resulting in the calibration path local oscillator signal (or calibration path local oscillator light) and the first delay signal S1. The calibration path local oscillator signal directly enters the mixer, while the first delay signal S1 enters the second beam splitter. The second beam splitter performs beam splitting on the first delay signal S1, obtaining at least two second delay signals (such as...). Figure 7 (S21, S22) and respectively enter at least two optical delay lines, that is, at least two second signals to be delayed after passing through the second beam splitter enter at least two optical delay lines respectively. It can be understood that after at least two second signals to be delayed are delayed by at least two optical delay lines, at least two delayed signals (such as...) can be obtained. Figure 7 (S21' and S22'). These delayed signals are respectively fed into the mixers corresponding to the optical delay lines. The mixers then perform frequency mixing on the received delayed signals and the calibration path local oscillator signals to obtain intermediate frequency (IF) signals. For example, one mixer mixes the received delayed signal S21' and the calibration path local oscillator signals to obtain IF signal Z1; another mixer mixes the received delayed signal S22' and the calibration path local oscillator signals to obtain IF signal Z2.

[0080] The signals processed by the mixer (such as the intermediate frequency signals Z1 and Z2 mentioned above) are detected by the corresponding photodetectors and converted into electrical signals, which are then output to the electrical combiner. The electrical combiner combines the signals detected by at least two photodetectors (i.e., at least two electrical signals). The combined electrical signal enters the amplifier and the analog-to-digital converter. The digital signal processed by the analog-to-digital converter enters the processing element, which then sends a feedback signal P to the drive circuit based on the digital signal. The drive circuit then adjusts the modulation signal L1 output to the light source based on the feedback signal P to calibrate the linearity between the modulation signal L1 and the light signal S output by the light source. For example, the intermediate frequency signal Z1 processed by mixer 1 is detected by photodetector 1 and converted into an electrical signal, which is then output to the electrical combiner; the intermediate frequency signal Z2 processed by mixer 2 is detected by photodetector 2 and converted into an electrical signal, which is then output to the electrical combiner. The signal output by the electrical combiner is then processed sequentially by the amplifier and the analog-to-digital converter. The digital signal, after being processed by the analog-to-digital converter, enters the processing element, which then sends a feedback signal P to the drive circuit based on the digital signal. The advantage of this is that multiple electrical signals are combined by an electrical combiner, so that multiple electrical signals are merged into one beam. This eliminates the need to set up amplifiers, analog-to-digital converters, and processing elements for each delayed signal, thereby reducing the number of optoelectronic devices.

[0081] The specific structure and function of each optoelectronic device shown in the above figures will be described below to provide an exemplary implementation scheme.

[0082] 1. Light source

[0083] Optionally, the light source can be any device capable of emitting light, such as a laser, including but not limited to: vertical cavity surface emitting laser (VCSEL), edge emitting laser (EEL), diode pump solid state laser (DPSSL), photonic crystal surface emitting laser (PCSEL), or fiber laser, etc.

[0084] In one example, the light source can emit a frequency-modulated continuous wave. In other words, the signal processing device can be a component of an FMCW LiDAR.

[0085] 2. Spectrometer

[0086] Optionally, the beam splitting element can be any device or combination of devices with beam splitting function, such as a beam splitter, a beam combiner / splitter, a combination of beam splitters, or a combination of beam splitters and beam combiners / splitters. It is understood that optical beam combiners and electrical beam combiners can be classified as beam splitting elements. Specifically, the beam splitting element can include the aforementioned first beam splitting element, second beam splitting element, and third beam splitting element.

[0087] It should be noted that the above beam splitters can be any type of beam splitter, including but not limited to: wavelength beam splitters, power beam splitters, polarization beam splitters, and other types of beam splitters.

[0088] 3. Optical beam combiner, electric beam combiner

[0089] Optionally, an optical combiner is an optical device that combines multiple optical signals into a single optical signal; an electrical combiner is an electronic device that combines multiple electrical signals into a single electrical signal. The optical combiner can be a beam combiner / splitter corresponding to the aforementioned beam splitter, and its function is to combine multiple light waves into one light wave.

[0090] Optionally, an optical combiner is an optical device with one or more selectable transmission ports, such as an optical switch. An optical switch can select a portion (e.g., one) of multiple optical signals for transmission, thus enabling processing of only a single delayed signal and reducing the cost of the required optical components. Similarly, an electrical combiner is an electronic device with one or more selectable transmission ports, such as an electrical switch. An electrical switch can select a portion (e.g., one) of multiple electrical signals for transmission. The factors influencing the switching on and off and the selection of signals by the electrical switch include, but are not limited to, signal quality, etc., and are not limited in this application.

[0091] 4. Optical Delay Line

[0092] As mentioned above, an optical delay line can be a component that delays the transmission of optical signals, and may include, but is not limited to, fiber optic delay lines or integrated waveguide delay lines. Fiber optic delay lines utilize the propagation of optical signals within optical fibers to achieve signal delay and typically have a relatively long length. Integrated waveguide delay lines, on the other hand, are waveguide devices fabricated on semiconductor chips. Their working principle involves controlling the propagation path length of electromagnetic waves in a dielectric waveguide, silicon, or other materials to achieve signal delay. The semiconductor materials used in integrated waveguide delay lines can be, for example, silicon (Si) or silicon nitride (SiN), and they transmit optical signals internally. Integrated waveguide delay lines offer numerous advantages, including, but not limited to, high integration density and smaller size.

[0093] In one possible implementation, any two of the at least two optical delay lines are made of different materials. Alternatively, any two of the at least two optical delay lines have different optical path lengths, which depend on at least one of the following factors: the length of the optical delay line, the thickness of the optical delay line, the material of the optical delay line, the design shape of the optical delay line, and the manufacturing process of the optical delay line. This design allows for different delays of the signal, improving accuracy during subsequent calibration and modulation. It also avoids the situation where all optical delay lines fail simultaneously or within a short period, compromising the reliability of the signal processing device.

[0094] 5. Mixer

[0095] A mixer performs frequency mixing on an input signal and outputs an intermediate frequency (IF) signal. The mixer can be any of the mixers described above. Optionally, the mixer can be a 180° mixer or a 90° mixer. A 180° mixer has two outputs and can coherently mix the calibration path local oscillator signal and the delay signal, resulting in a relative phase difference of 0° and 180° between the two outputs. A 90° mixer has four outputs and can coherently mix the calibration path local oscillator signal and the delay signal, resulting in relative phase differences of 0°, 90°, 180°, and 270° between the four outputs. And so on, not all of which will be listed here.

[0096] 6. Optical detection element

[0097] A photodetector, also known as a photodetector, is a device used to detect optical signals and convert them into electrical signals. A photodetector can be any of the photodetectors described above. Photodetectors are typically located after a mixer, thus enabling them to detect the intermediate frequency (IF) signal output by the mixer and convert it into an electrical signal. Optionally, examples of photodetectors include, but are not limited to: phototubes, photomultiplier tubes, photodiodes (PDs), avalanche photodiodes (APDs), and single-photon avalanche diodes (SPADs).

[0098] Taking a photodetector (PD) as an example, the photodetector element can include at least one PD, and the number of PDs can be the same as the number of output terminals of the mixer located in front of it. For example, when the mixer is a 180° mixer, the photodetector element includes two PDs, namely PD1 and PD2. The input terminals of PD1 and PD2 are respectively connected to the two output terminals of the 180° optical mixer. The output terminals of PD1 and PD2 are connected to the input terminal of an amplifier. PD1 and PD2 are used to detect signals with a relative phase difference of 0° and 180° output from the two output terminals of the 180° mixer, convert them into electrical signals, and then combine them on a single line to transmit them to the amplifier in a balanced detection manner. As another example, when the mixer is a 90° mixer, the photodetector element can specifically include four PDs, namely PD1, PD2, PD3, and PD4. The input terminals of the four PDs are respectively connected to the four output terminals of the 90° mixer. The output terminals of every two PDs are connected to the input terminal of an amplifier. Four detectors (PDs) are used to detect signals with relative phase differences of 0°, 90°, 180°, and 270° output from the four output terminals of the 90° mixer, convert them into electrical signals, and then combine them in pairs before transmitting them to the subsequent amplifier. The detection method of PD1, PD2, PD3, and PD4 is exemplified by a balanced detection method; this application is not limited to this method, and a detailed description is provided in the appendix below. Figure 8 To be continued Figure 13 .

[0099] 7. Amplifier

[0100] Optionally, the amplifier can be a component or combination of components with signal amplification capabilities. For example, it can include a trans-impedance amplifier (TIA). The TIA amplifies the useful signal in the input signal.

[0101] Taking a TIA as an example, an amplifier may include at least one TIA. The specific number of TIAs can be related to the number of photodetectors (PDs) contained in the photodetector element placed in front of it, for example, it can be half the number of PDs. A TIA can amplify the intermediate frequency signal with a certain degree of low noise.

[0102] Analog-to-digital converters can sample received analog signals that are continuous in time and amplitude, and convert them into digital signals that are discrete in time and amplitude, thereby simplifying the software processing operations of subsequent processing components.

[0103] Optionally, the analog-to-digital conversion element may include at least one analog-to-digital converter (ADC), and the number of ADCs may be the same as the number of TIAs contained in the amplifier positioned in front of it. The ADC is used to perform analog-to-digital conversion on the amplified intermediate frequency signal output from the TIA to obtain a digital signal.

[0104] 9. Processing Components

[0105] A processing element refers to a component with signal processing capabilities, such as a digital signal processor (DSP). A DSP can process one or more digital signals output from an analog-to-digital converter to obtain a feedback signal P, and then input the feedback signal P into the drive circuit.

[0106] The feedback signal can be used to calibrate the linearity between the modulation signal output from the driver circuit to the light source and the optical signal output from the light source; this is referred to as nonlinear calibration. There are various ways to achieve nonlinear calibration, including but not limited to frequency sweep monitoring and frequency modulation signal pre-distortion. Frequency sweep monitoring involves calculating the frequency sweep curve by monitoring changes in the modulation signal and determining whether the curve is linear. If it is not linear, it is calibrated to be linear. Frequency modulation signal pre-distortion refers to pre-compensating for modulation signals that will produce nonlinearity, ensuring that the compensated modulation signal is not distorted, i.e., maintaining linearity. Of course, other nonlinear calibration methods are possible, but specific limitations are not discussed here.

[0107] 10. Drive circuit

[0108] In each frequency-modulated photoelectric circuit, the driving circuit can generate a modulation signal based on the feedback signal output by the processing element, and input the modulation signal into the light source. The modulation signal is used to drive the light source to output a light signal whose frequency changes linearly with time, such as a light signal whose frequency changes linearly with time in the form of a triangular wave or a sawtooth wave. In some cases, the driving circuit also needs to be responsible for timing control functions, such as controlling the time window for the light source to emit light signals, and synchronizing with the receiving end (i.e., the receiving operation of the target measurement path) in order to accurately demodulate the information in the echo signal (i.e., the received signal).

[0109] Optionally, when the driving circuit receives multiple feedback signals, it can select the feedback signal with the best signal quality from the multiple feedback signals to generate a modulation signal based on the signal quality.

[0110] Based on the above detailed introduction of each optoelectronic device, the following example describes the above implementation scheme in further detail, taking a 180° or 90° mixer, a photodetector that may include at least one PD, an amplifier that is a TIA, an analog-to-digital converter that is an ADC, a processing element that is a DSP, a beam splitter that is a beam splitter, a laser that is a light source, and two optical delay lines.

[0111] Regarding the above implementation plan one, the following is provided: Figure 8 and Figure 9 Two structures. Please refer to [link / reference]. Figure 8 The diagram shows a schematic of the structure of a signal processing device provided in this application, including: a laser, a beam splitter 1 (third beam splitter element), a beam splitter 2 (first beam splitter element), a beam splitter 3 (second beam splitter element), two optical delay lines, an optical beam combiner, a 180° mixer, optical detection elements (including PD1 and PD2), a TIA, an ADC, a DSP, and a driving circuit.

[0112] The connection relationships of the various optoelectronic devices in this structure are as follows: the input terminal of the light source is connected to the output terminal of the driving circuit; the output terminal of the light source is connected to the input terminal of beam splitter 1; multiple output terminals of beam splitter 1 are respectively connected to the optoelectronic devices in the target measurement path and the input terminals of beam splitter 2; the first output terminal of beam splitter 2 is connected to the first input terminal of the 180° mixer; the second output terminal of beam splitter 2 is connected to the input terminal of beam splitter 3; the first output terminal of beam splitter 3 is connected to the input terminal of optical delay line 1; and the second output terminal of beam splitter 3 is connected to the input terminal of optical delay line 2. The optical delay line 1 is connected to the first input of the optical combiner, the output of the optical delay line 2 is connected to the second input of the optical combiner, the output of the optical combiner is connected to the second input of the 180° mixer, the two outputs of the 180° mixer are connected to the inputs of PD1 and PD2 respectively, the outputs of PD1 and PD2 are combined and connected to the input of TIA, the output of TIA is connected to the input of ADC, the output of ADC is connected to the input of DSP, and the output of DSP is connected to the driver circuit. The signal transmission flow of the loop formed by this structure can be referred to the above-described implementation scheme one, which will not be elaborated here.

[0113] Please see Figure 9 The diagram shows a schematic of the structure of a signal processing device provided in this application, including: a laser, a beam splitter 1 (third beam splitter element), a beam splitter 2 (first beam splitter element), a beam splitter 3 (second beam splitter element), two optical delay lines, an optical beam combiner, a 90° mixer, photodetectors (including PD1, PD2, PD3 and PD4), two TIAs, two ADCs, a DSP and a driving circuit.

[0114] The connection relationships of the various optoelectronic devices in this structure are as follows: the input terminal of the light source is connected to the output terminal of the driving circuit; the output terminal of the light source is connected to the input terminal of beam splitter 1; multiple output terminals of beam splitter 1 are respectively connected to the optoelectronic devices in the target measurement path and the input terminals of beam splitter 2; the first output terminal of beam splitter 2 is connected to the first input terminal of the 90° mixer; the second output terminal of beam splitter 2 is connected to the input terminal of beam splitter 3; the first output terminal of beam splitter 3 is connected to the input terminal of optical delay line 1; the second output terminal of beam splitter 3 is connected to the input terminal of optical delay line 2; the output terminal of optical delay line 1 is connected to the first input terminal of the optical combiner; and the output terminal of optical delay line 2... The output terminal of the optical beam combiner is connected to the second input terminal of the optical beam combiner. The output terminal of the optical beam combiner is connected to the second input terminal of the 90° mixer. The four output terminals of the 90° mixer are connected to the input terminals of PD1, PD2, PD3, and PD4, respectively. The output terminals of PD1 and PD2 are combined and connected to the input terminal of TIA1. The output terminals of PD3 and PD4 are combined and connected to the input terminal of TIA2. The output terminal of TIA1 is connected to the input terminal of ADC1. The output terminal of TIA2 is connected to the input terminal of ADC2. The output terminals of ADC1 and ADC2 are connected to the two input terminals of the DSP, respectively. The output terminal of the DSP is connected to the drive circuit. The signal transmission flow of the loop formed by this structure can refer to the above-described implementation scheme one, which will not be elaborated here.

[0115] Regarding the above-mentioned Implementation Plan 2, the following is provided: Figure 10 and Figure 11 Two structures. Please refer to [link / reference]. Figure 10 The diagram shows a schematic of the structure of a signal processing device provided in this application, including: a laser, a beam splitter 1 (third beam splitter element), a beam splitter 2 (first beam splitter element), a beam splitter 3 (second beam splitter element), two optical delay lines, a 180° mixer, two photodetectors (including PD1 and PD2), two TIAs, two ADCs, two DSPs, and a driving circuit.

[0116] The connection relationships of the various optoelectronic devices in this structure are as follows: the input terminal of the light source is connected to the output terminal of the driving circuit; the output terminal of the light source is connected to the input terminal of beam splitter 1; multiple output terminals of beam splitter 1 are respectively connected to the optoelectronic devices in the target measurement path and the input terminals of beam splitter 2; the first output terminal of beam splitter 2 is connected to the first input terminal of 180° mixer 1; the second output terminal of beam splitter 2 is connected to the first input terminal of 180° mixer 2; the third output terminal of beam splitter 2 is connected to the input terminal of beam splitter 3; the first output terminal of beam splitter 3 is connected to the input terminal of optical delay line 1; the second output terminal of beam splitter 3 is connected to the input terminal of optical delay line 2; the output terminal of optical delay line 1 is connected to the second input terminal of 180° mixer 1; and the output terminal of optical delay line 2 is connected to the 180° mixer... The second input terminal of mixer 2 is connected to the input terminals of PD1 and PD2 of a photodetector element, respectively. The two output terminals of mixer 2 are connected to the input terminals of PD1 and PD2 of another photodetector element, respectively. The output terminals of PD1 and PD2 of one photodetector element are combined and connected to the input terminal of TIA1. The output terminals of PD1 and PD2 of the other photodetector element are combined and connected to the input terminal of TIA2. The output terminal of TIA1 is connected to the input terminal of ADC1. The output terminal of TIA2 is connected to the input terminal of ADC2. The output terminal of ADC1 is connected to the input terminal of DSP1. The output terminal of ADC2 is connected to the input terminal of DSP2. The output terminals of DSP1 and DSP2 are both connected to the driver circuit. The signal transmission flow of the loop formed by this structure can be referred to the above-described implementation scheme two, which will not be elaborated here.

[0117] Please see Figure 11 The diagram shows a schematic of the structure of a signal processing device provided in this application, including: a laser, a beam splitter 1 (third beam splitter element), a beam splitter 2 (first beam splitter element), a beam splitter 3 (second beam splitter element), two optical delay lines, a 90° mixer, two photodetectors (including PD1, PD2, PD3, and PD4), four TIAs, four ADCs, two DSPs, and a driving circuit.

[0118] The connection relationships of the various optoelectronic devices in this structure are as follows: the input terminal of the light source is connected to the output terminal of the driving circuit; the output terminal of the light source is connected to the input terminal of beam splitter 1; multiple output terminals of beam splitter 1 are respectively connected to the optoelectronic devices in the target measurement path and the input terminals of beam splitter 2; the first output terminal of beam splitter 2 is connected to the first input terminal of 90° mixer 1; the second output terminal of beam splitter 2 is connected to the first input terminal of 90° mixer 2; the third output terminal of beam splitter 2 is connected to the input terminal of beam splitter 3; and the beam splitter... The first output terminal of beam splitter 3 is connected to the input terminal of optical delay line 1. The second output terminal of beam splitter 3 is connected to the input terminal of optical delay line 2. The output terminal of optical delay line 1 is connected to the second input terminal of 90° mixer 1. The output terminal of optical delay line 2 is connected to the second input terminal of 90° mixer 2. The four output terminals of 90° mixer 1 are respectively connected to the input terminals of photodetectors PD1, PD2, PD3, and PD4. The four output terminals of 90° mixer 2 are respectively connected to the input terminals of another photodetector PD1. The input terminals of PD1, PD2, PD3, and PD4 are connected. The output terminals of PD1 and PD2 of one photodetector are combined and connected to the input terminal of TIA1. The output terminals of PD3 and PD4 of one photodetector are combined and connected to the input terminal of TIA2. The output terminals of PD1 and PD2 of another photodetector are combined and connected to the input terminal of TIA3. The output terminals of another photodetector are combined and connected to the input terminal of TIA4. The output terminal of TIA1 is connected to the input terminal of ADC1. The output terminal of TIA2 is connected to the input terminal of ADC2. The output terminal of TIA3 is connected to the input terminal of ADC3. The output terminal of TIA4 is connected to the input terminal of ADC4. The output terminal of ADC1 is connected to the first input terminal of DSP1. The output terminal of ADC2 is connected to the second input terminal of DSP1. The output terminal of ADC3 is connected to the first input terminal of DSP2. The output terminal of ADC4 is connected to the second input terminal of DSP2. The output terminals of DSP1 and DSP2 are both connected to the driver circuit. The signal transmission flow of the loop formed by this structure can be referred to the above-described implementation scheme two, which will not be repeated here. Z11 can be understood as a part of the intermediate frequency signal Z1, and Z12 can be understood as another part of the intermediate frequency signal Z1; similarly, Z21 can be understood as a part of the intermediate frequency signal Z2, and Z22 can be understood as another part of the intermediate frequency signal Z2.

[0119] Regarding the above implementation plan three, the following is provided: Figure 12 and Figure 13 Two structures. Please refer to [link / reference]. Figure 12The diagram shows a schematic of a signal processing device provided in this application, including: a laser, a beam splitter 1 (third beam splitter element), a beam splitter 2 (first beam splitter element), a beam splitter 3 (second beam splitter element), two optical delay lines, a 180° mixer, two photodetectors (including PD1 and PD2), an electrical combiner, a TIA, an ADC, a DSP, and a driving circuit.

[0120] The connection relationships of the various optoelectronic devices in this structure are as follows: the input terminal of the light source is connected to the output terminal of the driving circuit; the output terminal of the light source is connected to the input terminal of beam splitter 1; multiple output terminals of beam splitter 1 are respectively connected to the optoelectronic devices in the target measurement path and the input terminals of beam splitter 2; the first output terminal of beam splitter 2 is connected to the first input terminal of 180° mixer 1; the second output terminal of beam splitter 2 is connected to the first input terminal of 180° mixer 2; the third output terminal of beam splitter 2 is connected to the input terminal of beam splitter 3; the first output terminal of beam splitter 3 is connected to the input terminal of optical delay line 1; the second output terminal of beam splitter 3 is connected to the input terminal of optical delay line 2; the output terminal of optical delay line 1 is connected to the second input terminal of 180° mixer 1; the optical delay... The output of late line 2 is connected to the second input of 180° mixer 2. The two outputs of 180° mixer 1 are respectively connected to the inputs of PD1 and PD2 of a photodetector. The two outputs of 180° mixer 2 are respectively connected to the inputs of PD1 and PD2 of another photodetector. The outputs of PD1 and PD2 of one photodetector are combined and connected to the first input of an electrical combiner. The outputs of PD1 and PD2 of the other photodetector are combined and connected to the second input of the electrical combiner. The output of the electrical combiner is connected to the input of TIA. The output of TIA is connected to the input of ADC. The output of ADC is connected to the input of DSP. The output of DSP is connected to the drive circuit. The signal transmission flow of the loop formed by this structure can be referred to the above-described implementation scheme three, which will not be elaborated here.

[0121] Please see Figure 13 The diagram shows a schematic of the structure of a signal processing device provided in this application, including: a laser, a beam splitter 1 (third beam splitter element), a beam splitter 2 (first beam splitter element), a beam splitter 3 (second beam splitter element), two optical delay lines, a 90° mixer, two photodetectors (including PD1, PD2, PD3, and PD4), two electrical combiners, two TIAs, two ADCs, a DSP, and a driving circuit.

[0122] The connection relationships of the various optoelectronic devices in this structure are as follows: the input terminal of the light source is connected to the output terminal of the driving circuit; the output terminal of the light source is connected to the input terminal of beam splitter 1; multiple output terminals of beam splitter 1 are respectively connected to the optoelectronic devices in the target measurement path and the input terminals of beam splitter 2; the first output terminal of beam splitter 2 is connected to the first input terminal of 90° mixer 1; the second output terminal of beam splitter 2 is connected to the first input terminal of 90° mixer 2; the third output terminal of beam splitter 2 is connected to the input terminal of beam splitter 3; the first output terminal of beam splitter 3 is connected to the input terminal of optical delay line 1; the second output terminal of beam splitter 3 is connected to the input terminal of optical delay line 2; the output terminal of optical delay line 1 is connected to the second input terminal of 90° mixer 1; the output terminal of optical delay line 2 is connected to the second input terminal of 90° mixer 2; the four output terminals of 90° mixer 1 are respectively connected to the input terminals of a photodetector element PD1, PD2, PD3, and PD4; the four output terminals of 90° mixer 2 are respectively connected to the input terminals of the optoelectronic devices in the target measurement path. Each output terminal is connected to the input terminals of PD1, PD2, PD3, and PD4 of another photodetector. The output terminals of PD1 and PD2 of one photodetector are combined and connected to the first input terminal of electrical combiner 1. The output terminals of PD3 and PD4 of one photodetector are combined and connected to the first input terminal of electrical combiner 2. The output terminals of PD1 and PD2 of another photodetector are combined and connected to the second input terminal of electrical combiner 1. The output terminals of PD3 and PD4 of another photodetector are combined and connected to the second input terminal of electrical combiner 2. The output terminal of electrical combiner 1 is connected to the input terminal of TIA1. The output terminal of electrical combiner 2 is connected to the input terminal of TIA2. The output terminal of TIA1 is connected to the input terminal of ADC1. The output terminal of TIA2 is connected to the input terminal of ADC2. The output terminal of ADC1 is connected to the first input terminal of DSP. The output terminal of ADC2 is connected to the second input terminal of DSP. The output terminal of DSP is connected to the driving circuit. The signal transmission flow of the loop formed by this structure can be referred to the above-described embodiment three, which will not be elaborated here. Z11 can be understood as a part of the intermediate frequency signal Z1, and Z12 can be understood as another part of the intermediate frequency signal Z1; similarly, Z21 can be understood as a part of the intermediate frequency signal Z2, and Z22 can be understood as another part of the intermediate frequency signal Z2.

[0123] Based on the structure and functional principles of the signal processing device described above, this application can also provide a detection device. Please refer to [link to relevant documentation]. Figure 14 The detection device 1400 includes a signal processing device 1410, which can be any of the signal processing devices described in the above embodiments, such as those described above. Figures 5-13 The signal processing device shown.

[0124] Alternatively, the detection device 1400 can be a lidar, such as an FMCW LiDAR.

[0125] Alternatively, as described above Figure 14 As shown, the detection device 1400 may also include a window 1420, which is used to protect the internal signal processing device 1410 and can transmit the light signal emitted by the signal processing device 1410.

[0126] It should be noted that, Figure 14 The given detection device architecture 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 specifically limit this.

[0127] Furthermore, any existing or future detection device with an optical delay line can adopt the above-described signal processing device structure design. Also, with the development of detection technology, the detection device structure provided in this application is equally applicable to the same technical problems, and this application does not specifically limit it in this regard.

[0128] Based on the structure and functional principles of the detection device described above, this application can also provide a terminal device. Please refer to [link / reference]. Figure 15 The terminal device 1500 includes a detection device 1510, which can be any of the detection devices described in the above embodiments, such as those described above. Figure 14 The detection device 1400 in the middle.

[0129] Optional, as described above Figure 15 As shown, the terminal device 1500 may further include a processor 1520, which is used to call programs or instructions to control the operation of the detection device 1510. Furthermore, the processor 1520 can also receive target-related information from the detection device 1510. When the terminal device 1500 is a vehicle, the processor 1520 can 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.

[0130] Furthermore, optionally, the terminal device 1500 may also include a memory 1530 for storing programs or instructions. Of course, the terminal device 1500 may also include other devices, such as wireless communication devices.

[0131] Processor 1520 may include one or more processing units. For example, processor 1520 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.

[0132] The memory 1530 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.

[0133] For example, the terminal device 1500 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.).

[0134] 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 one another. The technical features of different implementation schemes can be combined to form new implementation schemes based on their inherent logical relationships.

[0135] In this application, "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.

[0136] 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.

[0137] 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 "third," etc., 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 signal processing apparatus, characterized in that, It includes a light source, a first beam splitter, a second beam splitter, at least two optical delay lines, and a mixer; wherein the at least two optical delay lines are waveguide delay lines integrated on the chip, and the at least two optical delay lines are disposed one-to-one on at least two waveguide layers of the chip; The optical signal output by the light source enters the first beam splitter to obtain a calibration path local oscillator signal and a first delay signal. The calibration path local oscillator signal enters the mixer, and the first delay signal enters the second beam splitter. After passing through the second beam splitter, at least two second delay signals are respectively fed into at least two optical delay lines to obtain at least two delayed signals, which are then fed into the mixer.

2. The signal processing apparatus as described in claim 1, characterized in that, It also includes an interlayer coupler, which is disposed in any one of the at least two waveguide layers, and the second beam splitter and the input end of the interlayer coupler are disposed in the same waveguide layer; The interlayer coupler is connected between the second beam splitter and the at least two optical delay lines, except for the optical delay lines that are disposed in the same waveguide layer as the second beam splitter; The interlayer coupler is used to input the second delay signal corresponding to the other optical delay lines into the other optical delay lines respectively.

3. The signal processing apparatus as described in claim 1, characterized in that, It also includes photodetectors, processing units, and drive circuits; The signal after being mixed by the mixer is detected by the photodetector and converted into an electrical signal. The electrical signal is processed by the processing element to obtain a feedback signal, which is then input to the driving circuit. The feedback signal is used to adjust the modulation signal input to the light source by the driving circuit to calibrate the linearity of the light signal output by the light source.

4. The signal processing apparatus as described in claim 3, characterized in that, It also includes an optical beam combiner connected between the at least two optical delay lines and the mixer; The optical beam combiner is used to combine the at least two delayed signals.

5. The signal processing apparatus as described in claim 3, characterized in that, There are at least two mixers, and each of the at least two mixers is connected to one of the at least two delay lines; there are at least two processing elements, and each of the at least two processing elements is connected to one of the at least two mixers.

6. The signal processing apparatus as described in claim 4 or 5, characterized in that, It also includes an amplifier and an analog-to-digital converter, which are connected between the photodetector and the processing element.

7. The signal processing apparatus as described in claim 3, characterized in that, It also includes an electrical combiner connected between the photodetector and the processing element; there are at least two mixers, and each of the at least two mixers is connected to one of the at least two delay lines. The electrical combiner is used to combine the signals processed by the at least two mixers.

8. The signal processing apparatus as described in claim 7, characterized in that, It also includes an amplifier and an analog-to-digital converter, which are connected between the electrical combiner and the processing element.

9. The signal processing apparatus according to any one of claims 1-8, characterized in that, The materials of any two of the at least two optical delay lines are different.

10. The signal processing apparatus according to any one of claims 1-9, characterized in that, The mixer is a 180° mixer or a 90° mixer, and the mixer is used to perform mixing processing on the calibration path local oscillator signal and the signal after being delayed by the at least two optical delay lines.

11. A detection device, characterized in that, Includes the signal processing apparatus as described in any one of claims 1 to 10.

12. A terminal device, characterized in that, Includes the detection device as described in claim 11.

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