Optical detector, optical receiving system, optical detection method and chip

Abstract

The invention discloses an optical detector, an optical receiving system, an optical detection method and a chip, and belongs to the field of optical communication. The optical detector comprises a micro-ring detector and N micro-ring resonant cavities which are sequentially arranged and coupled, the first micro-ring resonant cavity is coupled with the waveguide, the micro-ring detector is coupled with the Nth micro-ring resonant cavity, and a first coupling coefficient between the waveguide and the first micro-ring resonant cavity is not smaller than a second coupling coefficient between the micro-ring detector and the Nth micro-ring resonant cavity; and the micro-ring detector is used for generating a first light current based on the target light signal, the first light current is used for detecting the intensity of the target light signal, and the target light signal is obtained by filtering the initial light signal transmitted in the waveguide through the micro-ring detector and the N micro-ring resonant cavities. The optical detector provided by the invention is higher in isolation degree.

Description

Technical Field

[0001] The present application relates to the field of optical communications, and in particular to an optical detector, an optical receiving system, an optical detection method and a chip. Background Art

[0002] In the process of optoelectronic communication, the transmitter sends optical signals of multiple different wavelengths to the receiver. The optical signals are transmitted through the transmission medium to the receiver. An optical receiving system is deployed on the chip of the receiver. The optical receiving system detects the optical signals through optical detectors to realize the reception of optical signals. Summary of the invention

[0003] The present application provides a light detector, a light receiving system, a light detection method and a chip to improve the isolation of light detection. The technical solution is as follows:

[0004] In a first aspect, a photodetector is provided, wherein the photodetector is coupled to a waveguide, the photodetector comprises a microring detector and N sequentially arranged microring resonant cavities, wherein N is an integer greater than or equal to 1, wherein a first microring resonant cavity among the N microring resonant cavities is coupled to the waveguide and a coupling coefficient is a first coupling coefficient, and the microring detector is coupled to an Nth microring resonant cavity among the N microring resonant cavities and a coupling coefficient is a second coupling coefficient, and the first coupling coefficient is greater than or equal to the second coupling coefficient;

[0005] The microring detector is used to generate a first photocurrent based on a target optical signal, and the first photocurrent is used to detect the intensity of the target optical signal. The target optical signal is obtained by filtering an initial optical signal transmitted in a waveguide by the microring detector and N microring resonant cavities.

[0006] N microring resonators and microring detectors jointly filter the initial optical signal to obtain the target optical signal, and generate a first photocurrent based on the target optical signal, which can detect the intensity of the target optical signal. Filtering the initial optical signal can ensure that the wavelength range of the filtered target optical signal is smaller and improve the isolation. In addition, the microring detector is directly coupled to the Nth microring resonator, which can reduce the insertion loss of the optical signal during transmission from the Nth microring resonator to the microring detector.

[0007] By making the first coupling coefficient between the waveguide and the first microring resonant cavity greater than the second coupling coefficient between the microring detector and the Nth microring resonant cavity, it is possible to ensure that the optical detector exhibits the expected broadband and realize the flat-top photocurrent response characteristic of optical detection, so as to detect more stable optical signals and reduce the difficulty of detection.

[0008] In a possible implementation, N is an integer greater than or equal to 2, two adjacent micro-ring resonant cavities in the N micro-ring resonant cavities are coupled, and the coupling coefficient between every two adjacent micro-ring resonant cavities in the N micro-ring resonant cavities is a third coupling coefficient; the first coupling coefficient is greater than or equal to the third coupling coefficient, and the second coupling coefficient is less than or equal to the third coupling coefficient. By ensuring the magnitude relationship among the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient, it is possible to further ensure that the photodetector exhibits an expected broadband and realize the characteristic of the flat-top photocurrent response of the photodetection.

[0009] In a possible implementation, N is an integer greater than 2, the third coupling coefficient between the intermediate resonant cavity and the previous microring resonant cavity is greater than or equal to the third coupling coefficient between the intermediate resonant cavity and the next microring resonant cavity, and the intermediate resonant cavity is a microring resonant cavity other than the first microring resonant cavity and the Nth microring resonant cavity among the N microring resonant cavities. The magnitude relationship between the third coupling coefficient between the intermediate resonant cavity and the previous microring resonant cavity and the third coupling coefficient between the intermediate resonant cavity and the next microring resonant cavity is limited to further ensure that the photodetector can exhibit the expected broadband and realize the characteristic of the flat-top photocurrent response of the photodetection.

[0010] In a possible implementation, the radii of the microring detector and the N microring resonant cavities are different. The radii of the microring detector and the N microring resonant cavities are different, which can make the free spectrum width of the microring detector and the N microring resonant cavities different, thereby increasing the effective free spectrum width wavelength interval between the microring detector and the N microring detectors, and further improving the isolation of light detection.

[0011] In a possible implementation, the loss coefficient of the microring detector is greater than the loss coefficient of each microring resonant cavity in the N microring resonant cavities. By limiting the magnitude relationship between the loss coefficient and the loss coefficient, it is possible to ensure that the optical detector exhibits the expected broadband and realize the flat-top photocurrent response characteristic of optical detection.

[0012] In a possible implementation, a first photoelectric conversion structure is provided on the microring detector; the first photoelectric conversion structure is used to generate a first photocurrent based on the target light signal. By providing the first photoelectric conversion structure on the microring detector, the conversion from the light signal to the photocurrent can be successfully achieved, and then the intensity of the light signal can be detected based on the photocurrent.

[0013] In a possible implementation, a first tuner is provided on the microring detector; the first tuner is used to adjust the first resonant wavelength of the microring detector to the wavelength of the target optical signal, and the first resonant wavelength is the center wavelength of the wavelength range of the target optical signal. By adjusting the first resonant wavelength by the first tuner, the target optical signal can be obtained by filtering based on the first resonant wavelength.

[0014] In a possible implementation, each of the N microring resonant cavities is provided with a second photoelectric conversion structure; the second photoelectric conversion structure is used to generate a second photocurrent, and the second photocurrent is used to detect the intensity of the target light signal. By providing the second photoelectric conversion structure on the N microring resonant cavities, the conversion from the light signal to the photocurrent can be successfully achieved, and then the intensity of the light signal can be detected based on the photocurrent.

[0015] In a possible implementation, each of the N microring resonant cavities is provided with a second tuner; the second tuner is used to adjust the second resonant wavelength of each microring resonant cavity to the wavelength of the target optical signal, and the second resonant wavelength is the center wavelength of the wavelength range of the optical signal transmitted by each microring resonant cavity. By adjusting the second resonant wavelength by the second tuner, the target optical signal can be obtained by filtering based on the second resonant wavelength.

[0016] In a second aspect, a light receiving system is provided, the light receiving system includes a light detection array, the light detection array includes a waveguide and at least one light detector, the at least one light detector is coupled to the waveguide, each light detector in the at least one light detector is a light detector in the first aspect and any possible implementation of the first aspect; the waveguide is used to receive the initial light signal emitted by the light transmitter; each light detector in the at least one light detector is used to generate a first photocurrent, the first photocurrent is used to detect the intensity of the light signal of the corresponding wavelength in the initial light signal, and the wavelength of the light signal detected by each light detector is different. By integrating at least one light detector, the light receiving system can realize parallel filtering and detection of different light signals transmitted in the waveguide, thereby improving the efficiency of light detection.

[0017] In a possible implementation, the optical receiving system further includes a receiving array and a receiving circuit, the receiving array includes at least one transimpedance amplifier and at least one operational amplifier, the number of at least one transimpedance amplifier and at least one operational amplifier is the same as the number of at least one photodetector, one transimpedance amplifier is connected to one operational amplifier, one transimpedance amplifier is connected to one photodetector, and at least one operational amplifier is connected to the receiving circuit; the transimpedance amplifier is used to convert the first photocurrent into a first photovoltage; the operational amplifier is used to amplify the first photovoltage to obtain the amplified photovoltage, and send the amplified photovoltage to the receiving circuit; the receiving circuit is used to receive the amplified photovoltage. The photocurrent is converted into a voltage by the transimpedance amplifier and the operational amplifier, and the photovoltage is sent to the receiving circuit to realize the detection of the optical signal.

[0018] In a third aspect, a light detection method is provided. The method is applied to a light detector, the light detector is coupled to a waveguide, the light detector includes a microring detector and N microring resonant cavities arranged in sequence, N is an integer greater than or equal to 1, the first microring resonant cavity among the N microring resonant cavities is coupled to the waveguide and the coupling coefficient is a first coupling coefficient, the microring detector is coupled to the Nth microring resonant cavity among the N microring resonant cavities and the coupling coefficient is a second coupling coefficient, and the first coupling coefficient is greater than or equal to the second coupling coefficient; the microring detector generates a first photocurrent based on a target light signal, the first photocurrent is used to detect the intensity of the target light signal, and the target light signal is obtained by filtering an initial light signal transmitted in the waveguide by the microring detector and the N microring resonant cavities.

[0019] In a possible implementation, N is an integer greater than or equal to 2, two adjacent micro-ring resonant cavities among the N micro-ring resonant cavities are coupled, and the coupling coefficient between every two adjacent micro-ring resonant cavities among the N micro-ring resonant cavities is a third coupling coefficient; the first coupling coefficient is greater than or equal to the third coupling coefficient, and the second coupling coefficient is less than or equal to the third coupling coefficient.

[0020] In a possible implementation, N is an integer greater than 2, a third coupling coefficient between the intermediate resonant cavity and the previous microring resonant cavity is greater than or equal to a third coupling coefficient between the intermediate resonant cavity and the subsequent microring resonant cavity, and the intermediate resonant cavity is a microring resonant cavity other than the first microring resonant cavity and the Nth microring resonant cavity among the N microring resonant cavities.

[0021] In a possible implementation, the radii of the micro-ring detector and the N micro-ring resonant cavities are different.

[0022] In a possible implementation, the loss coefficient of the microring detector is greater than the loss coefficient of each microring resonant cavity in the N microring resonant cavities.

[0023] In a possible implementation, a first photoelectric conversion structure is disposed on the microring detector; the microring detector generates a first photocurrent based on a target light signal, including: the first photoelectric conversion structure generates the first photocurrent based on the target light signal.

[0024] In a possible implementation, a first tuner is provided on the microring detector; before the microring detector generates a first photocurrent based on the target optical signal, the method further includes: the first tuner adjusts a first resonant wavelength of the microring detector to a wavelength of the target optical signal; the microring detector filters an initial optical signal based on the first resonant wavelength to obtain a target optical signal, wherein the first resonant wavelength is a central wavelength of a wavelength range of the target optical signal.

[0025] In a possible implementation, each of the N microring resonant cavities is provided with a second photoelectric conversion structure; the method further includes: the second photoelectric conversion structure generates at least one second photocurrent, and the second photocurrent is used to detect the intensity of the target light signal.

[0026] In a possible implementation, each of the N microring resonant cavities is provided with a second tuner; before the microring detector generates a first photocurrent based on the target optical signal, the method further includes: the second tuner adjusts the second resonant wavelength of the microring resonant cavity to the wavelength of the target optical signal; the microring resonant cavity filters the initial optical signal based on the second resonant wavelength to obtain the target optical signal, and the second resonant wavelength is the center wavelength of the wavelength range of the target optical signal.

[0027] According to a fourth aspect, a chip is provided, on which a light detector as in the first aspect and any possible implementation manner of the first aspect is deployed.

[0028] It should be understood that the beneficial effects achieved by the technical solutions of the third and fourth aspects of the present application and the corresponding possible implementation methods can be found in the above-mentioned technical effects of the first aspect and its corresponding possible implementation methods, and will not be repeated here. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 A schematic diagram of a use scenario of a micro-ring filter modulator provided in an embodiment of the present application;

[0030] Figure 2 A schematic diagram of the structure of an optical receiver based on micro-ring filter integration provided in an embodiment of the present application;

[0031] Figure 3 A schematic diagram of the structure of a light detector provided in an embodiment of the present application;

[0032] Figure 4 A schematic diagram of the structure of another optical detector provided in an embodiment of the present application;

[0033] Figure 5 A schematic diagram of the structure of another optical detector provided in an embodiment of the present application;

[0034] Figure 6 A schematic diagram of the structure of another optical detector provided in an embodiment of the present application;

[0035] Figure 7 A schematic diagram of the structure of another optical detector provided in an embodiment of the present application;

[0036] Figure 8 A schematic diagram of the structure of another optical detector provided in an embodiment of the present application;

[0037] Fig. 9 A schematic diagram of relative optical power provided in an embodiment of the present application;

[0038] Fig.10 Another schematic diagram of relative optical power provided in an embodiment of the present application;

[0039] Fig.11 A schematic diagram of the structure of a single micro-ring detector provided in an embodiment of the present application;

[0040] Fig.12 A schematic diagram of comparison results of a photocurrent response provided in an embodiment of the present application;

[0041] Fig.13 A schematic diagram of a process flow of a light detection method provided in an embodiment of the present application;

[0042] Fig.14 A schematic diagram of the structure of a light detection array provided in an embodiment of the present application;

[0043] Fig.15 A schematic diagram of the structure of an optical receiving system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0044] The terms used in the implementation section of this application are only used to explain the specific embodiments of this application and are not intended to limit this application.

[0045] With the emergence of large-scale artificial intelligence (AI) models based on large amounts of data, such as the chat generative pre-trained transformer (ChatGPT), AI technology has been continuously developing and iterating. Specifically, larger amounts of data require AI models to have stronger data throughput capabilities in order to move enough data into the AI ​​model within a limited time and pass it between the various sub-modules of the AI ​​model. Although a larger data scale can train more complex AI models, it also means that there needs to be more layers inside the AI ​​model, and therefore faster data throughput capabilities are needed to enhance the advantages of large-scale AI models.

[0046] AI models usually require large-scale clusters consisting of tens of thousands of graphics processing units (GPUs) or other dedicated parallel data processors. The high bandwidth memory (HBM), communication bandwidth, and power consumption between large-scale clusters are the main bottlenecks limiting the scale of clusters. Due to the limited communication bandwidth and power consumption that can be achieved by high-speed interconnection technology through cables at the scale of high-performance computing (HPC) or AI clusters. In this case, in order to achieve high-speed interconnection between large-scale clusters, the trend of optical fiber replacing copper is becoming more and more obvious, that is, the development of optical input and output (OIO) technology is getting faster and faster, and gradually replacing traditional electrical communications based on copper and other cables.

[0047] Microring-based wavelength division multiplexing (WDM) transceiver technology is one of the implementation solutions of OIO technology. Microring resonator (MRR) modulator is a modulator based on WDM technology. Compared with the traditional Mach-Zehnder modulator (MZM), MRR modulator has a low single-wave rate, but it is small in size and low in power consumption. In addition, MRR modulator has wavelength selectivity and can multiplex multiple wavelengths through WDM, so that the single-fiber rate of MRR modulator is higher than that of MZM.

[0048] The WDM in the MRR-based integrated WDM transmitter is generated by multiple micro-ring modulation at the transmitting end, and the signal of each wavelength needs to be filtered by multiple optical detectors at the receiving end, and then detected separately and finally converted into an electrical signal. Among them, the micro-ring is a micro-ring resonant cavity, which can also be called a micro-ring filter. The single-fiber rate of the micro-ring-based transceiver technology can be determined by the product of the single-wave rate and the number of wavelengths. Therefore, the more channels there are, that is, the more wavelengths the micro-ring can receive, the more channels based on the micro-ring, and the higher the bandwidth interconnection rate can be achieved.

[0049] For example, see Figure 1 , showing a schematic diagram of a usage scenario of an MRR modulator. Figure 1The left side shows a transmitter resonant microring modulation structure, including a light source, such as a quantum dash multi-wavelength laser (QDMWL). The QDMWL can emit optical signals of multiple wavelengths and transmit them to a transmitter array connected to the waveguide through a waveguide. The transmitter array includes multiple microrings, which are coupled to the same waveguide. Different microrings can filter and modulate optical signals of different wavelengths.

[0050] Each wavelength emitted by the laser in the WDM transmitter can be aligned with the central operating wavelength of each microring. Since the microring has wavelength selectivity, each microring will only modulate the optical signal with the same central operating wavelength as the microring, and then transmit the modulated optical signals of different wavelengths to the waveguide, thereby transmitting modulated optical signals of multiple wavelengths in the waveguide at the same time.

[0051] The right side of the figure shows the receiver resonant micro-ring structure. The receiving end filters signals of different wavelengths through the same micro-ring structure as the transmitting end. After each micro-ring filters the corresponding wavelength signal, it is connected to a photo detector (PD) for light detection and realizes the reception of WDM optical signals.

[0052] Since the isolation of a single microring for wavelength selection is not enough, that is, the ratio of the required optical signal in the filtered optical signal to all the filtered optical signals is small, and the filtering accuracy of the optical signal is not enough, a microring filter at the receiving end may not be able to completely block signals of other wavelengths from entering the PD connected to the filter, which will cause the signal detected by the PD to degrade, and ultimately reflect as the bit error rate of the signal. Due to the low isolation characteristics of a single microring, the filter spectrum response curve of a single microring is usually a pointed Lorentz line shape, which makes the detected optical power fluctuate greatly and also causes signal degradation. If many wavelength channels composed of single microrings are integrated on a waveguide, crosstalk will occur between different channels, further causing the signal detected by the PD to degrade, so it is impossible to integrate many wavelength channels based on a single microring. Therefore, the optical receiver integrated with a single microring filter cannot meet the needs of large-capacity transmission.

[0053] See also Figure 2, shows a schematic diagram of the structure of an optical receiver based on microring filter integration. Optical signals of different wavelengths are input from one end of the waveguide and pass through multiple channels, such as channel 1 to channel 4. The interval between two adjacent channels can be 50 micrometers (μm). Two coupled microrings are used for filtering in one channel. The coupling of two microrings can provide higher wavelength selectivity, which can better avoid intercepting the power of other channels and reduce the bit error rate of PD. In addition, the coupling of multiple microrings supports a flat filtering line type, that is, a flat-top line type. Flat filtering will make the optical power fluctuation smaller, which is beneficial to reduce the bit error rate during PD detection.

[0054] However, there will be loss when transmitting optical signals between two coupled microrings, and there is also insertion loss between the microring and the connected PD. Therefore, simply increasing the number of microrings to improve the isolation of optical detection will result in low optical signal power received by the PD after microring filtering. Even if the isolation of multiple microrings is higher, if the loss caused by multiple microring coupling filtering is greater, the advantage of high isolation may no longer exist. Therefore, there is an urgent need for an optical detector that can improve the isolation of optical detection.

[0055] For example, see Figure 3 , which is a schematic diagram of the structure of a light detector provided in an embodiment of the present application. The light detector is coupled to a waveguide 31, and the light detector includes a microring detector (MRR PD) 33 and N microring resonant cavities 32, wherein N is an integer greater than or equal to 1. The N microring resonant cavities 32 are arranged in sequence between the waveguide 31 and the microring detector 33. The waveguide 31 is coupled to the first microring resonant cavity among the N microring resonant cavities 32, the microring detector 33 is coupled to the Nth microring resonant cavity among the N microring resonant cavities 32, and the N microring resonant cavities 32 and the microring detector 33 are integrated in the same channel. If N is an integer greater than 1, two adjacent microring resonant cavities 32 among the N microring resonant cavities 32 are coupled. Figure 3 As shown, the microring detector 33 has a form similar to that of the microring resonant cavity. The microring detector 33 not only includes the structure of the microring resonant cavity, but also integrates some functions of the PD, so that the PD is integrated inside the filter, which can reduce the insertion loss between the microring resonant cavity 32 and the microring detector 33. The microring detector 33 not only has wavelength selectivity, but also has the function of filtering optical signals based on wavelength. It can also further improve the isolation of the channel by coupling with N microring resonant cavities 32, that is, improve the isolation and accuracy of optical detection.

[0056] Below, the composition and function of each structure in the photodetector are described in detail.

[0057] N micro-ring resonators and micro-ring detectors can jointly filter the initial optical signal transmitted in the waveguide to obtain a target optical signal, and the wavelength range of the target optical signal is smaller than the wavelength range of the initial optical signal.

[0058] For example, see Figure 4 The schematic diagram of the structure of a light detector is shown. The initial light signal can be transmitted in the waveguide, and the initial light signal includes light signals of different wavelengths. Figure 4 The initial optical signal includes the optical signals to be acquired by N micro-ring resonators and micro-ring detectors.

[0059] A first tuner may also be provided on the microring detector. The first tuner may be used to adjust the first resonant wavelength of the microring detector to the wavelength of the target optical signal, where the first resonant wavelength is the center wavelength of the wavelength range of the target optical signal. A second tuner is provided on the N microring resonant cavities, where the second tuner is used to adjust the second resonant wavelength of each microring resonant cavity to the wavelength of the target optical signal, where the second resonant wavelength is the center wavelength of the wavelength range of the optical signal transmitted by each microring resonant cavity. It is precisely because the second resonant wavelength of the N microring resonant cavities is the wavelength of the target optical signal that the N microring resonant cavities can obtain an optical signal including the target optical signal from the multiple optical signals transmitted by the waveguide.

[0060] For example, Figure 4 The rectangle 1 on the first microring resonator is the second tuner on the first microring resonator, and the second tuner adjusts the second resonant wavelength of the first microring resonator to the wavelength λ of the target optical signal. The first microring resonator can obtain an optical signal including the target optical signal in the initial optical signal transmitted by the waveguide based on the second resonant wavelength, and the central wavelength of the optical signal is λ. Figure 4 The rectangle 2 on the microring detector is a first tuner on the microring detector. The first tuner adjusts the first resonant wavelength of the microring detector to the wavelength λ of the target optical signal.

[0061] When the optical detector is working, since the optical detector is located in a channel, each microring resonant cavity and the microring detector need their own tuners to align their own resonant wavelengths to the wavelength of the target optical signal, so that the center wavelength of the wavelength range of the optical signal transmitted in the channel is the same. Since the first resonant wavelength of the microring detector is the same as the second resonant wavelength of the N microring resonant cavities, the microring detector and the N microring resonant cavities can filter the initial optical signal together based on the same resonant wavelength to obtain the target optical signal, and make most of the target optical signal distributed in the microring detector, so that the microring detector generates a first photocurrent based on the target optical signal.

[0062] The following is an exemplary description of the process in which N microring resonators and microring detectors jointly filter the initial optical signal and obtain the target optical signal, wherein the filtering may be a process of changing the distribution of optical signals of different wavelengths in each microring resonator and microring detector.

[0063] The first microring resonator obtains an optical signal corresponding to the second resonant wavelength from the initial optical signal transmitted in the waveguide, filters out the optical signal having a wavelength greatly different from that of the target optical signal, and continues to transmit the filtered optical signal.

[0064] If N is 1, the optical signal after filtering by the first microring resonant cavity is directly transmitted to the microring detector, and the microring detector filters the optical signal after filtering by the first microring resonant cavity again, so that the optical signal distributed in the microring detector is close to containing only the target optical signal. The optical signal after the microring detector filters again is the target optical signal, or in other words, the optical signal distributed in the microring detector after filtering is the target optical signal.

[0065] If N is a number greater than 1, the N microring resonators can filter the optical signal in turn, and the microring detector then filters the optical signal after multiple filtering to obtain the target optical signal. Taking N as 2 as an example, the second microring resonator obtains the optical signal after filtering by the first microring resonator. Since the second microring resonator can also be provided with a second tuner, the second resonant wavelength of the second microring resonator can also be the wavelength of the target optical signal. After obtaining the optical signal after filtering by the first microring resonator, the second microring resonator uses the wavelength of the target optical signal as the center wavelength to filter the optical signal after filtering by the first microring resonator again. The microring detector can filter the optical signal after filtering by the second microring resonator again, so that the optical signal distributed in the microring detector is close to containing only the target optical signal. The optical signal after filtering again by the microring detector is the target optical signal, or in other words, the optical signal distributed in the microring detector after filtering is the target optical signal.

[0066] In a possible implementation, a first photoelectric conversion structure is provided on the microring detector. The first photoelectric conversion structure is used to generate a first photocurrent based on the target light signal, so that the microring detector can generate the first photocurrent based on the target light signal. The first photocurrent is used to detect the intensity of the target light signal.

[0067] The present application embodiment does not limit the composition of the first photoelectric conversion structure. For example, the first photoelectric conversion structure can be a diode or a structure similar to a diode, for example, a PN junction or a PIN junction provided on the microring detector, that is, an N-type (electron conductive) doping region and a P-type (hole conductive) doping region are provided on the microring detector. Figure 4 , the annular waveguide (represented by a solid circle) of the microring detector is provided with two different doping materials (represented by a dotted circle and a double-line circle) on both sides inside and outside, respectively. The two different doping materials constitute an N-type doping region and a P-type doping region, respectively. The area near the interface of the two doping regions is a PN junction. Among them, the annular waveguide can be a silicon (Si) waveguide. Alternatively, the first photoelectric conversion structure can be a structure integrated by III-V compound materials, and the III-V compound materials include gallium arsenide (GaAs) and indium phosphide (InP), etc.

[0068] Alternatively, on the basis of setting a PN junction or a PIN junction on the micro-ring detector, germanium (Ge) can be epitaxially grown on the ring waveguide of the micro-ring detector, and Ge can be doped. Figure 5 In the structure of the photodetector shown, the incompletely closed circular ring on the microring detector is the epitaxial Ge.

[0069] Regardless of the composition of the first photoelectric conversion structure arranged on the microring detector, a voltage can be applied to both ends of the microring detector, so that the first photoelectric conversion structure absorbs photons in the target light signal to generate electron-hole pairs, that is, to generate photogenerated carriers, and then generate Figure 4 The first photocurrent shown. Optionally, there are many light absorption mechanisms of the first photoelectric conversion structure, including two-photon absorption (TPA) effect, free carrier absorption (FCA) effect, defect state absorption (DSA) effect and surface state absorption (SSA) effect, etc., which are not limited in the embodiments of the present application.

[0070] In addition to the above basic structure and the functions corresponding to the basic structure, the optical detector provided in the embodiment of the present application may also have different features to achieve different functions. The following takes features 1 to 4 as examples to illustrate the different features of the optical detector.

[0071] Feature 1: The coupling coefficient decreases.

[0072] The coupling coefficient between the waveguide and the first microring resonant cavity is the first coupling coefficient, and the coupling coefficient between the microring detector and the Nth microring resonant cavity is the second coupling coefficient, and the first coupling coefficient is greater than the second coupling coefficient. By limiting the magnitude relationship between the first coupling coefficient and the second coupling coefficient, it is possible to ensure that the optical detector exhibits an expected broadband and realize the characteristic of the flat-top photocurrent response of optical detection, so that a more stable optical signal can be detected, reducing the difficulty of detection.

[0073] For example, Figure 6 The optical detector shown includes a micro-ring resonant cavity, which is coupled to both the waveguide and the micro-ring detector. The first coupling coefficient between the micro-ring resonant cavity and the waveguide is μ1, and the second coupling coefficient between the micro-ring resonant cavity and the micro-ring detector is μ2. The relationship that the first coupling coefficient μ1 and the second coupling coefficient μ2 need to comply with is μ1>μ2 or μ1≥μ2.

[0074] In a possible implementation, N is an integer greater than or equal to 2, that is, there are two or more micro-ring resonant cavities between the waveguide and the micro-ring detector, and the coupling coefficient between every two adjacent micro-ring resonant cavities in the N micro-ring resonant cavities is the third coupling coefficient. In this implementation, the first coupling coefficient is greater than or equal to the third coupling coefficient, and the second coupling coefficient is less than or equal to the third coupling coefficient.

[0075] For example, Figure 7 The optical detector shown includes two micro-ring resonant cavities, wherein the first coupling coefficient between the first micro-ring resonant cavity and the waveguide is μ1, the third coupling coefficient between the second micro-ring resonant cavity and the first micro-ring resonant cavity is μ2, and the second coupling coefficient between the micro-ring detector and the second micro-ring resonant cavity is μ3. The first coupling coefficient μ1, the third coupling coefficient μ2 and the second coupling coefficient μ3 need to comply with the relationship of μ1>μ2>μ3 or μ1≥μ2≥μ3.

[0076] Optionally, if N is an integer greater than 2, the third coupling coefficient between the intermediate resonant cavity and the previous microring resonant cavity is greater than or equal to the third coupling coefficient between the intermediate resonant cavity and the next microring resonant cavity, and the intermediate resonant cavity is a microring resonant cavity among the N microring resonant cavities except the first microring resonant cavity and the Nth microring resonant cavity.

[0077] For example, Figure 3 The optical detector shown includes a plurality of micro-ring resonant cavities, the first coupling coefficient between the first micro-ring resonant cavity and the waveguide is μ1, the third coupling coefficient between the i-th micro-ring resonant cavity and the previous micro-ring resonant cavity is μ i , the third coupling coefficient between the i-th microring resonator and the next microring resonator is μ i+1 , the second coupling coefficient between the Nth microring resonator and the microring detector is μ N+1 , the relationship that each coupling coefficient needs to comply with is μ1>μ i >μ i+1 >μ N+1 Or μ1 ≥ μ i ≥μ i+1 ≥μ N+1 . Wherein, i is an integer greater than 1 and less than or equal to N-1.

[0078] Regardless of the value of N, that is, the number of microring resonant cavities, the coupling coefficient between the two microring resonant cavities decreases in the order of arrangement from the waveguide to the microring detector, thereby ensuring that the photodetector exhibits the expected broadband and realizes the flat-top photocurrent response characteristic of photodetection.

[0079] Feature 2: The micro-ring radii are different.

[0080] The microring radius is the radius of the microring detector or the radius of N microring resonant cavities. The free spectrum range (FSR) of the microring resonant cavity or microring detector can be defined according to the following formula (1). Where λ is the operating wavelength, that is, the resonant wavelength of the microring resonant cavity or microring detector, R is the radius of the microring resonant cavity or microring detector, and n is g is the microring waveguide group refractive index, and pi is the pi.

[0081] FSR=λ 2 / (2*pi*R*n g ) (1)

[0082] When microring resonators and microring detectors of different radii are coupled, the effective FSR of the entire microring system (i.e., a channel) is enlarged. FSR is the wavelength interval between two adjacent resonance peaks of a microring resonator or a microring detector. By changing the radius of a microring resonator or a microring detector, that is, assigning different radii to different microring resonators and microring detectors, the effective FSR wavelength interval can be increased, thereby allowing the optical receiver to accommodate more channels with different wavelengths and increase communication capacity.

[0083] like Figure 8 As shown, taking the coupling of two micro-ring resonant cavities with different radii as an example, the radius of the micro-ring resonant cavity is R1, the radius of the micro-ring detector is R2, and R1≠R2. The effective FSR of the micro-ring system composed of the micro-ring resonant cavity and the micro-ring detector satisfies the following formula (2), that is, the effective FSR is expanded to the lowest common multiple (lcm) of the FSRs corresponding to the original radii. Among them, FSR1 is the FSR corresponding to R1, and FSR2 is the FSR corresponding to R2.

[0084] FSR effective =1cm(FSR1, FSR2) (2)

[0085] For example, if FSR1=8 nanometers (nm) and FSR2=10 nm, the effective FSR of the entire system is 1 cm (8, 10)=40 nm.

[0086] In a possible implementation, the radii of the microring detector and the N microring resonant cavities are different, thereby maximizing the effective FSR of the channel. Optionally, the radii of the microring detector and the N microring resonant cavities may be partially the same, for example, the microring detector may be the same as the radius of one or more microring resonant cavities in the N microring resonant cavities, or the microring detector and the N microring resonant cavities have different radii, but there are two or more microring resonant cavities with the same radius in the N microring resonant cavities.

[0087] Feature 3: The microring detector has the largest loss coefficient.

[0088] Since the optical signal needs to be refracted and reflected continuously when it is transmitted in the N micro-ring resonant cavities and the micro-ring detector, a certain loss will be generated in the process of transmitting the optical signal between the micro-ring detector and the N micro-ring resonant cavities, which reduces the intensity of the optical signal. The micro-ring detector and the N micro-ring resonant cavities can have different loss coefficients.

[0089] In a possible implementation, the loss coefficient of the microring detector is greater than the loss coefficient of each microring resonant cavity in the N microring resonant cavities.

[0090] For example, Figure 5 In the structure of the optical detector shown, the loss coefficient of the microring resonant cavity is α1, the loss coefficient of the microring detector is α2, and the relationship that the loss coefficient α1 and the loss coefficient α2 need to satisfy is α1<α2.

[0091] If N is an integer greater than 1, the loss coefficient of the i-th microring resonator is α i , i is an integer greater than or equal to 1 and less than or equal to N. The loss coefficient of the detector is α N+1 . Then the relationship that each loss coefficient needs to satisfy is α i <α N+1 Optionally, the embodiment of the present application only needs to ensure that the loss coefficient of the microring detector is greater than the loss coefficient of the N microring resonant cavities, and does not limit the magnitude relationship between the loss coefficients of each microring resonant cavity in the N microring resonant cavities.

[0092] Optionally, the loss coefficient of the microring detector may be the same as the loss coefficient of the N microring resonant cavities. Specifically, the loss coefficient of the microring detector may be the same as the loss coefficient of the N microring resonant cavities, the loss coefficient of the microring detector may be the same as the loss coefficient of some of the N microring resonant cavities, or the loss coefficient of the microring detector may be different from the loss coefficient of the N microring resonant cavities, but the loss coefficient of some of the N microring resonant cavities is the same. Regardless of whether the loss coefficient of the microring detector is the same as the loss coefficient of all or part of the N microring resonant cavities, it is necessary to ensure that the loss coefficient of the microring detector is the maximum loss coefficient.

[0093] Feature 4: Multi-microring photoelectric conversion.

[0094] Each of the N microring resonant cavities is provided with a second photoelectric conversion structure, and the second photoelectric conversion structure is used to generate a second photocurrent, and the second photocurrent is used to detect the intensity of the target optical signal. Since the multiple coupled microring resonant cavity structures make wavelength alignment more difficult, the microring resonant cavity can be provided with a second photoelectric conversion structure that absorbs optical power and generates photocurrent, so that the optical power value of the target optical signal in each microring resonant cavity can be detected, that is, the intensity of the target optical signal in each microring resonant cavity, so as to check whether the resonant wavelength of each microring resonant cavity is aligned with the wavelength of the target optical signal, and can also enrich the detection resources and improve the detection accuracy.

[0095] For example, see Figure 7 The second photoelectric conversion structure is disposed on both microring resonant cavities. The second photoelectric conversion structure on the first microring resonant cavity generates a current I corresponding to the optical signal transmitted in the first microring resonant cavity. m1 The second photoelectric conversion structure on the second microring resonant cavity generates a current I corresponding to the optical signal transmitted in the second microring resonant cavity. m2 . The composition of the second photoelectric conversion structure may be the same as or different from that of the first photoelectric conversion structure, and the embodiments of the present application do not limit this. Since the optical power value of the target optical signal in each microring resonant cavity is detected, it can only be used to detect whether the resonant wavelength of each microring resonant cavity is aligned with the wavelength of the target optical signal. Therefore, the current generated by the second photoelectric conversion structure can be reduced. For example, the second photoelectric conversion structure can be set only for part of the position of the microring resonant cavity, or the volume of the second photoelectric conversion structure can be reduced to obtain a smaller second photocurrent.

[0096] Optionally, a second photoelectric conversion structure may be provided on some of the N micro-ring resonant cavities to verify the wavelengths of some of the micro-ring resonant cavities.

[0097] The optical detector provided in the embodiment of the present application may have one or more of the above-mentioned features 1 to 4, so that the optical detector provided in the embodiment of the present application has higher isolation and lower loss.

[0098] See also Fig. 9 , taking the simulation results of a microring resonant cavity and a microring detector coupling as an example, the effect of the optical detector provided in the embodiment of the present application is explained. Fig. 9Schematic diagram of the relative optical power in the waveguide through port, the first microring resonator, and the microring detector. The horizontal axis is the wavelength offset relative to the wavelength of the target optical signal, that is, the magnitude of the frequency detuning, in gigahertz (GHz). The vertical axis is the relative optical power, in decibels (dB). Fig. 9 It can be seen that when the wavelength gradually approaches the central wavelength (the horizontal axis is 0), the optical power is gradually captured by the microring detector and the first microring resonant cavity, so the curve at the series end begins to be concave, and the optical power in the microring detector and the first microring resonant cavity (light intensity in the ring) gradually increases. When it continues to approach the central wavelength, the power at the series end continues to decrease, and at this time the optical power in the waveguide of the first microring resonant cavity begins to be captured by the microring detector. Then, near the central wavelength, almost all the optical power is concentrated in the microring detector.

[0099] Fig.10 Another schematic diagram of relative optical power is shown. Fig.11 The simulation results of the single microring detector shown in the figure are obtained by simulating the single microring detector. The single microring detector only includes one microring structure of the microring detector, but does not include other microring resonant cavities, that is, the microring detector is directly coupled to the waveguide.

[0100] Fig.10 and Fig. 9 There are two obvious differences. Difference 1: The curve of the optical power in the microring detector changes from a flat top to a pointed top. The optical power changes more obviously with the wavelength in the microring detector. Therefore, more precise wavelength alignment is required for a single microring detector, which is not conducive to the practical application of the microring detector structure. Difference 2: The power at the crosstalk end at 100 GHz drops from -0.1 dB to -0.26 dB, which means that the single microring detector still absorbs the energy of optical signals outside the corresponding working wavelength, which is not conducive to the integration of multiple channels and will cause crosstalk between different channels.

[0101] Fig.12 Schematic diagram of the comparison of the photocurrent responses of the two structures. Fig.12 It can be seen that in order to achieve the same optical bandwidth (-20GHz to 20GHz), the current response of a single microring detector varies more significantly with wavelength, has a lower peak current, and has a slower current roll-off outside the center wavelength. The current response of a dual microring detector (a microring resonant cavity coupled to a microring detector) varies more stably with wavelength, has a higher peak current, and has a faster current roll-off outside the center wavelength. By comparison, it can be seen that optical detectors with multiple microring structures can better achieve a flat-top curve, reduce the absorption of energy from other optical signals, have higher isolation for optical detection, and are less difficult to detect the intensity of the target optical signal.

[0102] In summary, the optical detector provided in the embodiment of the present application is based on one or more micro-ring resonant cavities and micro-ring detector coupling, and can have wavelength selectivity with higher isolation.

[0103] Exemplarily, the microring detector has not only a filtering function, but also a detection function. That is, integrating the functions of a traditional PD into a microring can reduce the number of components of the photodetector. Since the microring detector is integrated inside the channel and realizes the transmission of optical signals based on coupling with the microring resonant cavity, the photodetector provided in the embodiment of the present application can also reduce the insertion loss caused by the transmission of optical signals from the microring resonant cavity to the connected PD, thereby reducing the overall loss of the photodetector. Each component of the photodetector satisfies one or more of features one to four, so that a flat-top response can be successfully achieved, the required broadband, and a high extinction ratio can be achieved.

[0104] In addition, since the optical detector provided in the embodiment of the present application has the characteristic of high isolation, each channel does not respond to the optical signal transmitted in the adjacent channel, reducing the crosstalk between different channels, thereby supporting multi-channel integration. In short, the optical detector can be integrated with ultra-high wavelength density and still ensure high isolation of adjacent channels while having minimal additional insertion loss.

[0105] Accordingly, the present application also provides a light detection method, which can be applied to Figure 3 The light detector shown. The flow chart of this method can be found in Fig.13 , including but not limited to S1301.

[0106] S1301, the microring detector generates a first photocurrent based on a target optical signal, the first photocurrent is used to detect the intensity of the target optical signal, and the target optical signal is obtained by filtering an initial optical signal transmitted in a waveguide by the microring detector and N microring resonant cavities.

[0107] The method executed by each structure in S1301 can refer to the above description of the function of each structure of the light detector, which will not be repeated here.

[0108] In addition, an embodiment of the present application further provides an optical receiving system, the optical receiving system includes an optical detection array, the optical detection array includes a waveguide and at least one optical detector, at least one optical detector is respectively coupled to the waveguide, and each optical detector in the at least one optical detector is an optical detector having one or more characteristics as described above. The waveguide is used to receive an initial optical signal emitted by an optical transmitter. Each optical detector in the at least one optical detector is used to generate a first photocurrent, and the first photocurrent is used to detect the intensity of an optical signal of a corresponding wavelength in the initial optical signal, and the wavelengths of the optical signals detected by each optical detector are different.

[0109] For example, the structure of the light detection array can be seen in Fig.14 The optical detection array is an array of cascaded optical detectors, each channel is aligned to a different wavelength, and each detects WDM channel information of different wavelengths. For example, channel (CH) 1, channel 2, and channel n correspond to target signals of n different wavelengths.

[0110] The waveguide transmits WDM signals of multiple wavelengths. When a specific wavelength passes through the corresponding optical detector, for example, when the optical signal of wavelength 1 passes through CH1, the optical signal will be captured by the first microring resonator in channel 1, enter channel 1, and finally be absorbed by the microring detector in channel 1. The absorbed optical power will generate a first photocurrent (Iph).

[0111] In one possible implementation, the optical receiving system also includes a receiving array and a receiving circuit (receiver circuit), the receiving array includes at least one transimpedance amplifier and at least one operational amplifier, the number of at least one transimpedance amplifier and the number of at least one operational amplifier are the same as the number of at least one photodetector, one transimpedance amplifier is connected to one operational amplifier, one transimpedance amplifier is connected to one photodetector, and at least one operational amplifier is connected to the receiving circuit; the transimpedance amplifier is used to convert the first photocurrent into a first photovoltage; the operational amplifier is used to amplify the first photovoltage to obtain the amplified photovoltage, and send the amplified photovoltage to the receiving circuit; the receiving circuit is used to receive the amplified photovoltage.

[0112] For example, the structure of the complete optical receiving system can be seen in Fig.15 . Each microring detector in the photodetector can be connected to a transimpedance amplifier (TIA), and the transimpedance amplifier can be connected to an operational amplifier (AMP). Since the signal rate received by each microring detector is relatively low (generally 8G bits per second (bps) to 56Gbps), the first photocurrent generated based on the optical signal with a lower rate is also relatively small. Therefore, after the first photocurrent is converted into a first photovoltage by the transimpedance amplifier and amplified by the operational amplifier, the optical signal transmitted through the optical fiber can be restored, and can directly enter the receiving circuit and its connected signal processing unit and register without the need for a serializer / deserializer (SerDes) to convert the rate of the optical signal, thereby reducing latency and reducing costs.

[0113] In summary, the DWDM optical receiving array based on microring detectors can achieve single-fiber high-capacity communication by integrating multi-wavelength channels.

[0114] The embodiment of the present application also provides a chip, on which the light detector provided by the embodiment of the present application is deployed. A light detector can be integrated into a chip or integrated into a module on a chip. The chip can be integrated with a main chip. The main chip can be, for example, a central processing unit (CPU), a GPU, a neural network processing unit (NPU), and a deep learning processing unit (DPU). The chip can be integrated with the main chip on an interposer and provide an OIO interconnection channel for the main chip.

[0115] In addition, the receiving array can also be integrated into a separate chip, or it can be integrated on a chip with the transmitter array.

[0116] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in this application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integration. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk Solid State Disk), etc.

[0117] In this application, the terms "first", "second", etc. are used to distinguish between identical or similar items with substantially the same effects and functions. It should be understood that there is no logical or temporal dependency between "first", "second", and "nth", nor is there a limitation on the quantity and execution order. It should also be understood that although the following description uses the terms first, second, etc. to describe various elements, these elements should not be limited by the terms. These terms are only used to distinguish one element from another element.

[0118] It should also be understood that in the various embodiments of the present application, the size of the serial number of each process does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0119] The term "at least one" in this application means one or more, and the term "multiple" in this application means two or more, for example, multiple second devices means two or more second devices. The terms "system" and "network" are often used interchangeably herein.

[0120] It should be understood that the terms used in the description of the various examples herein are only for describing specific examples and are not intended to be limiting. As used in the description of the various examples and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0121] It should also be understood that the term "and / or" used herein refers to and encompasses any and all possible combinations of one or more of the associated listed items. The term "and / or" is a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this application generally indicates that the associated objects before and after are in an "or" relationship.

[0122] It should also be understood that the terms "if" and "if" may be interpreted to mean "when" or "upon" or "in response to determining" or "in response to detecting." Similarly, the phrases "if it is determined that ..." or "if [a stated condition or event] is detected" may be interpreted to mean "upon determining that ..." or "in response to determining that ..." or "upon detecting [a stated condition or event]" or "in response to detecting [a stated condition or event]," depending on the context.

[0123] The above description is only an embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present application shall be included in the protection scope of the present application.

Claims

1. A light detector, characterized in that: The photodetector is coupled to the waveguide, the photodetector comprises a microring detector and N sequentially arranged microring resonant cavities, wherein N is an integer greater than or equal to 1, a first microring resonant cavity among the N microring resonant cavities is coupled to the waveguide and a coupling coefficient is a first coupling coefficient, the microring detector is coupled to an Nth microring resonant cavity among the N microring resonant cavities and a coupling coefficient is a second coupling coefficient, and the first coupling coefficient is greater than or equal to the second coupling coefficient; The microring detector is used to generate a first photocurrent based on a target optical signal, and the first photocurrent is used to detect the intensity of the target optical signal. The target optical signal is obtained by filtering an initial optical signal transmitted in the waveguide by the microring detector and the N microring resonant cavities.

2. The optical detector according to claim 1, characterized in that The N is an integer greater than or equal to 2, two adjacent micro-ring resonant cavities in the N micro-ring resonant cavities are coupled, and the coupling coefficient between every two adjacent micro-ring resonant cavities in the N micro-ring resonant cavities is a third coupling coefficient; the first coupling coefficient is greater than or equal to the third coupling coefficient, and the second coupling coefficient is less than or equal to the third coupling coefficient.

3. The optical detector according to claim 2, characterized in that The N is an integer greater than 2, the third coupling coefficient between the intermediate resonant cavity and the previous microring resonant cavity is greater than or equal to the third coupling coefficient between the intermediate resonant cavity and the next microring resonant cavity, and the intermediate resonant cavity is a microring resonant cavity among the N microring resonant cavities except the first microring resonant cavity and the Nth microring resonant cavity.

4. The optical detector according to any one of claims 1 to 3, characterized in that: The radii of the micro-ring detector and the N micro-ring resonant cavities are different.

5. The optical detector according to any one of claims 1 to 4, characterized in that: The loss coefficient of the micro-ring detector is greater than the loss coefficient of each micro-ring resonant cavity in the N micro-ring resonant cavities.

6. The optical detector according to any one of claims 1 to 5, characterized in that: The micro-ring detector is provided with a first photoelectric conversion structure; The first photoelectric conversion structure is used to generate the first photocurrent based on the target light signal.

7. The photodetector according to any one of claims 1 to 6, characterized in that: The micro-ring detector is provided with a first tuner; The first tuner is used to adjust the first resonant wavelength of the microring detector to the wavelength of the target optical signal, and the first resonant wavelength is the central wavelength of the wavelength range of the target optical signal.

8. The photodetector according to any one of claims 1 to 7, characterized in that: A second photoelectric conversion structure is disposed on each of the N microring resonant cavities; The second photoelectric conversion structure is used to generate a second photocurrent, and the second photocurrent is used to detect the intensity of the target light signal.

9. The optical detector according to any one of claims 1 to 8, characterized in that: A second tuner is provided on each of the N micro-ring resonant cavities; The second tuner is used to adjust the second resonant wavelength of each microring resonant cavity to the wavelength of the target optical signal, and the second resonant wavelength is the central wavelength of the wavelength range of the optical signal transmitted by each microring resonant cavity.

10. A light receiving system, characterized in that: The optical receiving system comprises an optical detection array, the optical detection array comprises a waveguide and at least one optical detector, the at least one optical detector is respectively coupled to the waveguide, and each optical detector in the at least one optical detector is an optical detector according to any one of claims 1 to 9; The waveguide is used to receive the initial optical signal emitted by the optical transmitter; Each photodetector in the at least one photodetector is used to generate a first photocurrent, and the first photocurrent is used to detect the intensity of a light signal of a corresponding wavelength in the initial light signal. The wavelengths of the light signals detected by each photodetector are different.

11. The optical receiving system according to claim 10, characterized in that: The optical receiving system further includes a receiving array and a receiving circuit, wherein the receiving array includes at least one transimpedance amplifier and at least one operational amplifier, the number of the at least one transimpedance amplifier and the number of the at least one operational amplifier are the same as the number of the at least one photodetector, one transimpedance amplifier is connected to one operational amplifier, one transimpedance amplifier is connected to one photodetector, and the at least one operational amplifier is connected to the receiving circuit; The transimpedance amplifier is used to convert the first photocurrent into a first photovoltage; The operational amplifier is used to amplify the first photovoltage to obtain an amplified photovoltage, and send the amplified photovoltage to the receiving circuit; The receiving circuit is used to receive the amplified photovoltage.

12. A light detection method, characterized in that: The method is applied to a photodetector, wherein the photodetector is coupled to a waveguide, the photodetector comprises a microring detector and N sequentially arranged microring resonant cavities, wherein N is an integer greater than or equal to 1, a first microring resonant cavity among the N microring resonant cavities is coupled to the waveguide and a coupling coefficient is a first coupling coefficient, the microring detector is coupled to an Nth microring resonant cavity among the N microring resonant cavities and a coupling coefficient is a second coupling coefficient, and the first coupling coefficient is greater than or equal to the second coupling coefficient; The microring detector generates a first photocurrent based on a target optical signal, and the first photocurrent is used to detect the intensity of the target optical signal. The target optical signal is obtained by filtering an initial optical signal transmitted in the waveguide by the microring detector and the N microring resonant cavities.

13. The method according to claim 12, characterized in that The N is an integer greater than or equal to 2, two adjacent micro-ring resonant cavities in the N micro-ring resonant cavities are coupled, and the coupling coefficient between every two adjacent micro-ring resonant cavities in the N micro-ring resonant cavities is a third coupling coefficient; the first coupling coefficient is greater than or equal to the third coupling coefficient, and the second coupling coefficient is less than or equal to the third coupling coefficient.

14. The method according to claim 12 or 13, characterized in that The N is an integer greater than 2, the third coupling coefficient between the intermediate resonant cavity and the previous microring resonant cavity is greater than or equal to the third coupling coefficient between the intermediate resonant cavity and the next microring resonant cavity, and the intermediate resonant cavity is a microring resonant cavity among the N microring resonant cavities except the first microring resonant cavity and the Nth microring resonant cavity.

15. The method according to any one of claims 12 to 14, characterized in that: The radii of the micro-ring detector and the N micro-ring resonant cavities are different.

16. The method according to any one of claims 12 to 15, characterized in that: The loss coefficient of the micro-ring detector is greater than the loss coefficient of each micro-ring resonant cavity in the N micro-ring resonant cavities.

17. The method according to any one of claims 12 to 16, characterized in that: The micro-ring detector is provided with a first photoelectric conversion structure; The microring detector generates a first photocurrent based on a target light signal, comprising: The first photoelectric conversion structure generates the first photocurrent based on the target light signal.

18. The method according to any one of claims 12 to 17, characterized in that: The micro-ring detector is provided with a first tuner; Before the microring detector generates a first photocurrent based on the target light signal, the microring detector further includes: The first tuner adjusts the first resonant wavelength of the microring detector to the wavelength of the target optical signal; The microring detector filters the initial optical signal based on the first resonant wavelength to obtain the target optical signal, where the first resonant wavelength is a central wavelength of a wavelength range of the target optical signal.

19. The method according to any one of claims 12 to 18, characterized in that: A second photoelectric conversion structure is disposed on each of the N microring resonant cavities; The method further comprises: The second photoelectric conversion structure generates at least one second photocurrent, and the second photocurrent is used to detect the intensity of the target light signal.

20. The method according to any one of claims 12 to 19, characterized in that: A second tuner is provided on each of the N micro-ring resonant cavities; Before the microring detector generates a first photocurrent based on the target light signal, the microring detector further includes: The second tuner adjusts the second resonance wavelength of the microring resonator to the wavelength of the target optical signal; The microring resonator filters the initial optical signal based on the second resonant wavelength to obtain the target optical signal, where the second resonant wavelength is a central wavelength of a wavelength range of the target optical signal.

21. A chip, characterized in that: The chip is provided with a light detector as claimed in any one of claims 1 to 9.

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