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

Abstract

An optical detector, an optical receiving system, an optical detection method and a chip. The optical detector comprises a micro-ring detector (33) and N micro-ring resonant cavities (32) which are successively arranged and coupled, the first micro-ring resonant cavity (32) being coupled to a waveguide (31), the micro-ring detector (33) being coupled to the N-th micro-ring resonant cavity (32), and a first coupling coefficient between the waveguide (31) and the first micro-ring resonant cavity (32) being not less than a second coupling coefficient between the micro-ring detector (33) and the N-th micro-ring resonant cavity (32). The micro-ring detector (33) is used for generating a first photocurrent on the basis of a target optical signal, the first photocurrent being used for measuring the intensity of the target optical signal, and the target optical signal being obtained by means of the micro-ring detector (33) and the N micro-ring resonant cavities (32) filtering an initial optical signal transmitted in the waveguide (31). The isolation degree of the optical detector is higher.

Description

Light detector, light receiving system, light detection method and chip

[0001] This application claims priority to Chinese patent application No. 202311107881.2 filed on August 29, 2023, entitled “Photodetector, Photoreceiving System, Photodetection Method and Chip,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The present application relates to the field of optical communications, and in particular to a light detector, a light receiving system, a light detection method, and a chip. Background Art

[0003] 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.

[0004] Summary of the Invention

[0005] This 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:

[0006] In a first aspect, a photodetector is provided. The photodetector is coupled to a waveguide, and the photodetector includes a microring detector and N sequentially arranged microring resonant cavities, where 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 with a first coupling coefficient, and the microring detector is coupled to an Nth microring resonant cavity among the N microring resonant cavities with a second coupling coefficient, where the first coupling coefficient is greater than or equal to the second coupling coefficient.

[0007] The microring detector is used to generate a first photocurrent based on a target optical signal. 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 N microring resonant cavities.

[0008] N microring resonators and a microring detector jointly filter the initial optical signal to obtain a target optical signal. Based on the target optical signal, a first photocurrent is generated, enabling detection of the intensity of the target optical signal. Filtering the initial optical signal ensures that the wavelength range of the filtered target optical signal is narrower, improving isolation. Furthermore, the microring detector is directly coupled to the Nth microring resonator, reducing insertion loss during the transmission of the optical signal from the Nth microring resonator to the microring detector.

[0009] 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, the optical detector can exhibit the expected broadband and realize the flat-top photocurrent response characteristic of optical detection, thereby detecting more stable optical signals and reducing the difficulty of detection.

[0010] In one possible implementation, N is an integer greater than or equal to 2, two adjacent micro-ring resonators in the N micro-ring resonators are coupled, and the coupling coefficient between every two adjacent micro-ring resonators in the N micro-ring resonators 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 relationship between the first coupling coefficient, the second coupling coefficient, and the third coupling coefficient, the photodetector can be further guaranteed to exhibit the desired broadband and achieve the flat-top photocurrent response characteristic of photodetection.

[0011] In one possible implementation, N is an integer greater than 2, the third coupling coefficient between the intermediate resonant cavity and the preceding microring resonant cavity is greater than or equal to the third coupling coefficient between the intermediate resonant cavity and the succeeding microring resonant cavity, and the intermediate resonant cavity is a microring resonant cavity other than the first and Nth microring resonants among the N microring resonants. The relationship between the third coupling coefficient between the intermediate resonant cavity and the preceding microring resonant cavity and the third coupling coefficient between the intermediate resonant cavity and the succeeding microring resonant cavity is defined to further ensure that the photodetector exhibits the desired broadband performance and achieves the flat-top photocurrent response characteristic of photodetection.

[0012] In one possible implementation, the microring detector and the N microring resonant cavities have different radii. This allows the free spectrum widths of the microring detector and the N microring resonant cavities to differ, thereby increasing the effective free spectrum width wavelength spacing between the microring detector and the N microring resonant cavities, further improving optical detection isolation.

[0013] In one possible implementation, the loss coefficient of the microring detector is greater than the loss coefficient of each of the N microring resonators. By limiting the magnitude relationship between the loss coefficients, the photodetector can exhibit the desired broadband performance and achieve the flat-top photocurrent response characteristic of photodetection.

[0014] In one possible implementation, a first photoelectric conversion structure is provided on the microring detector; the first photoelectric conversion structure is configured to generate a first photocurrent based on a target light signal. By providing the first photoelectric conversion structure on the microring detector, the light signal can be successfully converted into a photocurrent, and the intensity of the light signal can be detected based on the photocurrent.

[0015] In one possible implementation, a first tuner is provided on the microring detector. The first tuner is configured to adjust a first resonant wavelength of the microring detector to the wavelength of a target optical signal, where the first resonant wavelength is the center wavelength of a wavelength range of the target optical signal. By adjusting the first resonant wavelength with the first tuner, the target optical signal can be filtered based on the first resonant wavelength.

[0016] In one possible implementation, each of the N microring resonators is provided with a second photoelectric conversion structure. This second photoelectric conversion structure is configured to generate a second photocurrent, which is used to detect the intensity of the target optical signal. By providing the second photoelectric conversion structure on each of the N microring resonators, the optical signal can be successfully converted into a photocurrent, and the intensity of the optical signal can then be detected based on the photocurrent.

[0017] In one possible implementation, each of the N microring resonators is provided with a second tuner. The second tuner is configured to adjust a second resonant wavelength of each microring resonator to the wavelength of a target optical signal, where the second resonant wavelength is the center wavelength of a wavelength range of the optical signal transmitted by each microring resonator. By adjusting the second resonant wavelength by the second tuner, the target optical signal can be filtered based on the second resonant wavelength.

[0018] In a second aspect, an optical receiving system is provided. The optical receiving system includes an optical detection array, the optical detection array including a waveguide and at least one optical detector, the at least one optical detector being coupled to each waveguide, each optical detector in the at least one optical detector being an optical detector according to the first aspect and any possible implementation of the first aspect. The waveguide is configured to receive an initial optical signal emitted by an optical transmitter. Each optical detector in the at least one optical detector is configured to generate a first photocurrent, the first photocurrent being used to detect the intensity of an optical signal having a corresponding wavelength in the initial optical signal. The wavelengths of the optical signals detected by each optical detector are different. By integrating the at least one optical detector, the optical receiving system can filter and detect different optical signals transmitted in the waveguide in parallel, thereby improving the efficiency of optical detection.

[0019] In one 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 the at least one transimpedance amplifier and the at least one operational amplifier are equal to 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 at least one operational amplifier is connected to the receiving circuit. The transimpedance amplifier is configured to convert a first photocurrent into a first photovoltage. The operational amplifier is configured to amplify the first photovoltage to obtain an amplified photovoltage and transmit the amplified photovoltage to the receiving circuit. The receiving circuit is configured to receive the amplified photovoltage. The transimpedance amplifier and the operational amplifier convert the photocurrent into a voltage, amplify it, and transmit the photovoltage to the receiving circuit to detect the optical signal.

[0020] In a third aspect, a light detection method is provided. The method is applied to a light detector, wherein the light detector is coupled to a waveguide, and the light detector includes a microring detector and N sequentially arranged microring resonant cavities, where N is an integer greater than or equal to 1, and the first microring resonant cavity among the N microring resonant cavities is coupled to the waveguide with a first coupling coefficient, and the microring detector is coupled to the Nth microring resonant cavity among the N microring resonant cavities with a second coupling coefficient, where 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, and 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.

[0021] 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 a 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.

[0022] 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 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.

[0023] In a possible implementation, the radii of the micro-ring detector and the N micro-ring resonant cavities are different.

[0024] 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.

[0025] In a possible implementation, a first photoelectric conversion structure is provided 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.

[0026] In one possible implementation, a first tuner is provided on the microring detector. Before the microring detector generates a first photocurrent based on a 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; and the microring detector filters an initial optical signal based on the first resonant wavelength to obtain a target optical signal, where the first resonant wavelength is a center wavelength of a wavelength range of the target optical signal.

[0027] In one possible implementation, a second photoelectric conversion structure is provided on each of the N microring resonant cavities. 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 optical signal.

[0028] In one 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 a target optical signal, the method further includes: adjusting a second resonant wavelength of the microring resonant cavity to a wavelength of the target optical signal by the second tuner; and filtering an initial optical signal based on the second resonant wavelength to obtain a target optical signal in the microring resonant cavity, where the second resonant wavelength is a center wavelength of a wavelength range of the target optical signal.

[0029] In a fourth aspect, a chip is provided, on which a light detector as in the first aspect and any possible implementation of the first aspect is deployed.

[0030] It should be understood that the beneficial effects achieved by the technical solutions of the third and fourth aspects of this 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

[0031] FIG1 is a schematic diagram of a usage scenario of a micro-ring filter modulator provided in an embodiment of the present application;

[0032] FIG2 is a schematic structural diagram of an optical receiver based on microring filter integration provided in an embodiment of the present application;

[0033] FIG3 is a schematic diagram of the structure of a light detector provided in an embodiment of the present application;

[0034] FIG4 is a schematic diagram of the structure of another light detector provided in an embodiment of the present application;

[0035] FIG5 is a schematic structural diagram of another optical detector provided in an embodiment of the present application;

[0036] FIG6 is a schematic structural diagram of another optical detector provided in an embodiment of the present application;

[0037] FIG7 is a schematic structural diagram of another optical detector provided in an embodiment of the present application;

[0038] FIG8 is a schematic structural diagram of another optical detector provided in an embodiment of the present application;

[0039] FIG9 is a schematic diagram of relative optical power provided in an embodiment of the present application;

[0040] FIG10 is a schematic diagram of another relative optical power provided in an embodiment of the present application;

[0041] FIG11 is a schematic structural diagram of a single microring detector provided in an embodiment of the present application;

[0042] FIG12 is a schematic diagram showing comparison results of a photocurrent response according to an embodiment of the present application;

[0043] FIG13 is a schematic diagram of a flow chart of a light detection method provided in an embodiment of the present application;

[0044] FIG14 is a schematic diagram of the structure of a light detection array provided in an embodiment of the present application;

[0045] FIG15 is a schematic structural diagram of an optical receiving system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] 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.

[0047] 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 able to continuously develop and iterate. Specifically, larger amounts of data require AI models to have stronger data throughput capabilities in order to be able to move enough data into the AI ​​model within a limited time and pass it between the various sub-modules of the AI ​​model. While larger data scales can train more complex AI models, it also means that more layers are needed within the AI ​​model, and therefore faster data throughput capabilities are needed to enhance the advantages of large-scale AI models.

[0048] AI models typically require large-scale clusters consisting of tens of thousands of graphics processing units (GPUs) or other dedicated parallel data processors. However, high-bandwidth memory (HBM), communication bandwidth, and power consumption between large-scale clusters are the main bottlenecks limiting cluster size. High-speed interconnection via cables can only achieve limited communication bandwidth and power consumption at the scale of high-performance computing (HPC) or AI clusters. In this context, the trend of optical fiber replacing copper is becoming increasingly evident in order to achieve high-speed interconnection between large-scale clusters. This means that optical input and output (OIO) technology is developing at an increasingly rapid pace and is gradually replacing traditional electrical communications based on copper and other cables.

[0049] Microring-based wavelength division multiplexing (WDM) transceiver technology is one of the implementation solutions for OIO technology. The microring resonator (MRR) modulator is a modulator based on WDM technology. Compared with the traditional Mach-Zehnder modulator (MZM), the MRR modulator has a lower single-wavelength rate, but is compact and has low power consumption. In addition, the MRR modulator is wavelength-selective and can be used to multiplex multiple wavelengths through WDM, thereby achieving a single-fiber rate higher than that of the MZM.

[0050] In a WDM transmitter based on MRR integration, WDM is generated by modulation of multiple microrings at the transmitting end. At the receiving end, multiple optical detectors are required to filter the signal at each wavelength, detect it separately, and ultimately convert it into an electrical signal. The microring is a microring resonator, also known as a microring filter. The single-fiber rate of microring-based transceiver technology is determined by the product of the single-wavelength rate and the number of wavelengths. Therefore, the greater the number of channels, that is, the greater the number of wavelengths that the microring can receive, the greater the number of channels based on the microring, and the higher the bandwidth interconnection rate that can be achieved.

[0051] For example, referring to FIG1 , a schematic diagram of a use scenario of an MRR modulator is shown. The left side of FIG1 shows a transmitter resonant ring modulation structure, which includes a light source, such as a quantum dash multi-wavelength laser (QD MWL). The QD MWL can emit optical signals of multiple wavelengths and transmit them through a waveguide to a waveguide-connected transmitter array. The transmitter array includes multiple microrings, which are coupled to the same waveguide. Different microrings can filter and modulate optical signals of different wavelengths.

[0052] Each wavelength emitted by the laser in a WDM transmitter can be aligned with the central operating wavelength of each microring. Due to the wavelength selectivity of the microring, each microring only modulates the optical signal with the same wavelength as the central operating wavelength of the microring, and then transmits the modulated optical signal of a different wavelength into the waveguide, thereby simultaneously transmitting optical signals of multiple wavelengths modulated in the waveguide.

[0053] The right side of the figure shows the receiver resonant microring structure. The receiving end filters signals of different wavelengths through the same microring structure as the transmitting end. After each microring filters the corresponding wavelength signal, it is connected to a photo detector (PD) for optical detection and reception of WDM optical signals.

[0054] Because a single microring has insufficient wavelength-selective isolation—that is, the ratio of the desired optical signal to the total filtered optical signal is small, resulting in insufficient optical signal filtering accuracy—a single microring filter at the receiving end may not completely block signals of other wavelengths from entering the PD connected to it. This degrades the signal detected by the PD, ultimately manifesting as a bit error rate (BER). Due to the low isolation of a single microring, its filtering spectrum response curve typically exhibits a peaked Lorentzian curve, resulting in large fluctuations in the detected optical power and signal degradation. If multiple wavelength channels composed of single microrings are integrated on a waveguide, crosstalk between the different channels will occur, further degrading the signal detected by the PD. Therefore, integrating many wavelength channels within a single microring is unfeasible. Consequently, optical receivers integrated with a single microring filter cannot meet the requirements of high-capacity transmission.

[0055] Referring to Figure 2, a schematic diagram of the structure of an optical receiver based on microring filter integration is shown. 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 the 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, also known as a flat-top line type. Flat filtering will reduce the fluctuation of optical power, which is beneficial to reducing the bit error rate during PD detection.

[0056] However, there is loss when transmitting optical signals between two coupled microrings, and there is also insertion loss between the microrings and the connected PDs. Therefore, simply increasing the number of microrings to improve optical detection isolation results 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 the coupled filtering of multiple microrings is greater, the advantage of high isolation may no longer be achieved. Therefore, there is an urgent need for an optical detector that can improve the isolation of optical detection.

[0057] For example, see FIG3 , 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 includes a microring detector (MRR PD) 33 and N microring resonant cavities 32, where 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, and the microring detector 33 is coupled to the Nth microring resonant cavity among the N microring resonant cavities 32. The N microring resonant cavities 32 and the microring detector 33 are integrated into the same channel. If N is an integer greater than 1, then two adjacent microring resonant cavities 32 among the N microring resonant cavities 32 are coupled. As shown in FIG3 , 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 of the functions of the PD, realizing the integration of the PD 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.

[0058] The following is a detailed description of the composition and function of each structure in the photodetector.

[0059] The N microring resonators and the microring 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.

[0060] For example, see Figure 4, a schematic diagram of the structure of a photodetector. An initial optical signal can be transmitted in a waveguide. The initial optical signal includes optical signals of different wavelengths, which are represented by different arrows in Figure 4. The initial optical signal includes optical signals to be acquired by N microring resonators and the microring detector.

[0061] The microring detector may also be provided with a first tuner. The first tuner can 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 resonators, and the second tuner is used to adjust the second resonant wavelength of each microring resonator 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 resonator. Because the second resonant wavelength of the N microring resonators is the wavelength of the target optical signal, the N microring resonators can acquire an optical signal including the target optical signal from the multiple optical signals transmitted by the waveguide.

[0062] For example, rectangle 1 on the first microring resonator in Figure 4 represents the second tuner on the first microring resonator. This second tuner adjusts the second resonant wavelength of the first microring resonator to the wavelength λ of the target optical signal. Based on the second resonant wavelength, the first microring resonator can capture an optical signal including the target optical signal from the initial optical signal transmitted through the waveguide. This optical signal has a central wavelength of λ. Rectangle 2 on the microring detector in Figure 4 represents the first tuner on the microring detector. This first tuner adjusts the first resonant wavelength of the microring detector to the wavelength λ of the target optical signal.

[0063] When the photodetector is operating, since the photodetector is located within a channel, each microring resonant cavity and microring detector requires its own tuner to align its resonant wavelength with the wavelength of the target optical signal, so that the center wavelength of the wavelength range of the optical signal transmitted within the channel is the same. Because 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 jointly filter the initial optical signal based on the same resonant wavelength to obtain the target optical signal, and the majority of the target optical signal is distributed within the microring detector, allowing the microring detector to generate a first photocurrent based on the target optical signal.

[0064] The following is an exemplary description of the process in which N microring resonators and microring detectors jointly filter the initial optical signal to obtain the target optical signal. The filtering may be a process of changing the distribution of optical signals of different wavelengths within each microring resonator and microring detector.

[0065] The first microring resonator obtains an optical signal corresponding to the second resonant wavelength (e.g., the first optical signal shown in FIG4 ) from the initial optical signal transmitted in the waveguide, filters out the optical signal having a wavelength significantly different from that of the target optical signal, and continues to transmit the filtered optical signal.

[0066] If N is 1, the optical signal filtered by the first microring resonator is directly transmitted to the microring detector. The microring detector then filters the optical signal filtered by the first microring resonator again, so that the optical signal distributed within 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. In other words, the optical signal distributed within the microring detector after filtering is the target optical signal.

[0067] If N is a number greater than 1, the N microring resonators can filter the optical signal in sequence, 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 filtered 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 filtered by the first microring resonator, the second microring resonator filters the optical signal filtered by the first microring resonator again (for example, the second optical signal shown in FIG4 ) with the wavelength of the target optical signal as the center wavelength. The microring detector can further filter the optical signal filtered by the second microring resonator so that the optical signal distributed within the microring detector is close to containing only the target optical signal. The optical signal filtered by the microring detector again is the target optical signal, or in other words, the optical signal distributed within the microring detector after filtering is the target optical signal.

[0068] In one possible implementation, a first photoelectric conversion structure is provided on the microring detector. The first photoelectric conversion structure is configured to generate a first photocurrent based on a target light signal, enabling the microring detector to generate the first photocurrent based on the target light signal. The first photocurrent is used to detect the intensity of the target light signal.

[0069] The embodiments of the present application do 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 a 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. Referring to FIG4 , the ring 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 the inside and outside sides, respectively. The two different doping materials constitute an N-type doping region and a P-type doping region, respectively. The area near the interface between the two doping regions is a PN junction. The ring waveguide can be a silicon (Si) waveguide. Alternatively, the first photoelectric conversion structure can be a structure integrated with III-V compound materials, and the III-V compound materials include gallium arsenide (GaAs) and indium phosphide (InP).

[0070] Alternatively, based on the configuration of a PN junction or PIN junction in the microring detector, epitaxial germanium (Ge) can be grown on the ring waveguide of the microring detector and the Ge can be doped. For example, in the structure of the optical detector shown in Figure 5, the partially enclosed ring on the microring detector is epitaxial Ge.

[0071] Regardless of the composition of the first photoelectric conversion structure provided 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, generates electron-hole pairs, that is, generates photogenerated carriers, and then generates a first photocurrent (or simply referred to as photocurrent) as shown in Figures 4-6. 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.

[0072] In addition to the basic structure and the functions corresponding to the basic structure, the optical detector provided in the embodiment of the present application can also have different features to achieve different functions. The following uses features 1 to 4 as examples to illustrate the different features of the optical detector.

[0073] Feature 1: The coupling coefficient decreases.

[0074] The coupling coefficient between the waveguide and the first microring resonator is a first coupling coefficient, and the coupling coefficient between the microring detector and the Nth microring resonator is a second coupling coefficient, with the first coupling coefficient being greater than the second coupling coefficient. By limiting the magnitude relationship between the first and second coupling coefficients, the photodetector can be guaranteed to exhibit the desired broadband and achieve the flat-top photocurrent response characteristic of photodetection, thereby enabling the detection of more stable optical signals and reducing detection difficulty.

[0075] For example, the photodetector shown in Figure 6 includes a microring resonator that is coupled to both a waveguide and a microring detector. The first coupling coefficient between the microring resonator and the waveguide is μ1, and the second coupling coefficient between the microring resonator and the microring detector is μ2. The first coupling coefficient μ1 and the second coupling coefficient μ2 must comply with the relationship μ1>μ2 or μ1≥μ2.

[0076] In one possible implementation, N is an integer greater than or equal to 2. That is, there are two or more microring resonators between the waveguide and the microring detector. The coupling coefficient between every two adjacent microring resonators in the N microring resonators 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.

[0077] For example, the optical detector shown in FIG7 includes two microring resonators, wherein a first coupling coefficient between the first microring resonator and the waveguide is μ1, a third coupling coefficient between the second microring resonator and the first microring resonator is μ2, and a second coupling coefficient between the microring detector and the second microring resonator is μ3. The first coupling coefficient μ1, the third coupling coefficient μ2, and the second coupling coefficient μ3 must comply with the following relationship: μ1>μ2>μ3 or μ1≥μ2≥μ3.

[0078] 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 the microring resonant cavity other than the first microring resonant cavity and the Nth microring resonant cavity among the N microring resonant cavities.

[0079] For example, the photodetector shown in FIG3 includes multiple microring resonators, the first coupling coefficient between the first microring resonator and the waveguide is μ1, the third coupling coefficient between the i-th microring resonator and the previous microring resonator 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 follow is μ1>μi >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.

[0080] Regardless of the value of N, or the number of microring resonators, the coupling coefficient between the two microring resonators decreases in the order from the waveguide to the microring detector, thereby ensuring that the photodetector exhibits the expected broadband and achieves the flat-top photocurrent response characteristic of photodetection.

[0081] Feature 2: The micro-ring radii are different.

[0082] 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 the radius of the microring resonant cavity or microring detector. g is the microring waveguide group refractive index, and pi is the circumference. FSR = λ 2 / (2*pi*R*n g ) (1)

[0083] When microring resonators and microring detectors of different radii are coupled, the effective FSR of the entire microring system (i.e., a channel) is expanded. The FSR is the wavelength interval between two adjacent resonant peaks of a microring resonator or detector. By varying the radius of the microring resonator or detector—that is, assigning different radii to different microring resonators and detectors—the effective FSR wavelength interval can be increased. This, in turn, allows the optical receiver to accommodate more channels with different wavelengths, increasing communication capacity.

[0084] As shown in Figure 8, taking the coupling of two microring resonators with different radii as an example, the radius of the microring resonator is R1, the radius of the microring detector is R2, and R1≠R2. The effective FSR of the microring system composed of the microring resonator and the microring 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. FSR effective =lcm(FSR1,FSR2) (2)

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

[0086] In one possible implementation, the microring detector and the N microring resonant cavities have different radii, thereby maximizing the effective FSR of the channel. Alternatively, the microring detector and the N microring resonant cavities may have partially the same radii. For example, the microring detector may have the same radius as one or more of the N microring resonant cavities, or the microring detector and the N microring resonant cavities may have different radii, but two or more of the N microring resonant cavities may have the same radius.

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

[0088] Because the optical signal is constantly refracted and reflected as it propagates through the N microring resonators and the microring detector, a certain amount of loss occurs during the transmission of the optical signal between the microring detector and the N microring resonators, reducing the intensity of the optical signal. The microring detector and the N microring resonators 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, in the structure of the optical detector shown in FIG5 , the loss coefficient of the microring resonant cavity is α1, the loss coefficient of the microring detector is α2, and the loss coefficient α1 and the loss coefficient α2 need to satisfy the relationship 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 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, or the loss coefficient of the microring detector may be the same as the loss coefficient of some of the N microring resonant cavities. Alternatively, 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 may be the same. Regardless of whether the loss coefficient of the microring detector is the same as the loss coefficient of all or some 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 resonators is equipped with a second photoelectric conversion structure, which is used to generate a second photocurrent, which is used to detect the intensity of the target optical signal. Because wavelength alignment is more difficult due to multiple coupled microring resonator structures, the microring resonator can be equipped with a second photoelectric conversion structure that absorbs optical power and generates a photocurrent. This allows the optical power value of the target optical signal in each microring resonator, that is, the intensity of the target optical signal in each microring resonator, to be detected. This verifies whether the resonant wavelength of each microring resonator is aligned with the wavelength of the target optical signal. This also enriches detection resources and improves detection accuracy.

[0095] For example, referring to FIG7 , not only is a first photoelectric conversion structure capable of generating a first photocurrent provided on the microring detector, but a second photoelectric conversion structure is also provided on both microring resonant cavities. The second photoelectric conversion structure on the first microring resonant cavity generates a second photocurrent 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 second photocurrent 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 this is not limited in the embodiments of the present application. 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 in other words, 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 implement wavelength calibration 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] Please refer to Figure 9, which shows the simulation results of a microring resonator coupled with a microring detector as an example to illustrate the effect of the optical detector provided by the embodiment of the present application. Figure 9 is a schematic diagram of the relative optical power within 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). As can be seen from Figure 9, when the wavelength gradually approaches the center wavelength (the horizontal axis is 0), the optical power is gradually captured by the microring detector and the first microring resonator. Therefore, the curve of the through port begins to sink, and the optical power (intra-ring light intensity) within the microring detector and the first microring resonator gradually increases. When it continues to approach the center wavelength, the power of the through port continues to decrease, while the optical power within the first microring resonator waveguide begins to be captured by the microring detector. Then, near the center wavelength, almost all the optical power is concentrated in the microring detector.

[0099] Figure 10 shows another schematic diagram of relative optical power, which is a simulation result obtained by simulating the single microring detector shown in Figure 11. The single microring detector includes only one microring structure and does not include other microring resonant cavities. In other words, the microring detector is directly coupled to the waveguide and generates photocurrent.

[0100] Figure 10 shows two significant differences from Figure 9. Difference 1: The optical power curve within the microring detector changes from a flat top to a pointed top. The optical power varies more significantly with wavelength within the microring detector. Therefore, more precise wavelength alignment is required for a single microring detector, hindering the practical application of the microring detector structure. Difference 2: The power at the crosstalk end drops from -0.1dB to -0.26dB at 100GHz, indicating that a single microring detector still absorbs optical signal energy outside the corresponding operating wavelength. This is detrimental to the integration of multiple channels and can introduce crosstalk between different channels.

[0101] Figure 12 shows a schematic diagram comparing the photocurrent responses of the two structures. As shown in Figure 12, to achieve the same optical bandwidth (-20 GHz to 20 GHz), the current response of the single microring detector varies more significantly with wavelength, with a lower peak current and a slower current roll-off outside the center wavelength. In contrast, the current response of the dual microring detector (one microring resonator coupled to the microring detector) is more stable with wavelength, with a higher peak current and a faster current roll-off outside the center wavelength. This comparison shows that the multi-microring structure photodetector is more capable of achieving a flat-top curve and reduces the absorption of energy from other optical signals, resulting in higher isolation for optical detection and less difficulty in detecting 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 microring resonant cavities and microring detector coupling, and can have wavelength selectivity with higher isolation.

[0103] For example, 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 optical detector. 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 optical detector 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 optical detector. Each component of the optical detector satisfies one or more of the 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] Furthermore, due to the high isolation characteristics of the optical detectors provided in the embodiments of the present application, each channel does not respond to optical signals transmitted in adjacent channels, reducing crosstalk between different channels and thus supporting multi-channel integration. In short, optical detectors can be integrated at ultra-high wavelength density while still ensuring high isolation between adjacent channels and minimizing additional insertion loss.

[0105] Accordingly, the present embodiment further provides a light detection method, which can be applied to the light detector shown in Figure 3. The flowchart of the method can be seen in Figure 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. 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 methods executed by the various structures in S1301 can refer to the above description of the functions of the various structures of the light detector, and will not be repeated here.

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

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

[0110] The waveguide transmits WDM signals of multiple wavelengths. When a specific wavelength passes through the corresponding photodetector, for example, when a light signal of wavelength 1 passes through CH1, the light signal is captured by the first microring resonator in channel 1, enters channel 1, and is ultimately absorbed by the microring detector in channel 1. The absorbed optical power generates a first photocurrent (Iph).

[0111] In one possible implementation, the optical receiving system also includes a receiving array and a receiving circuit (receiver circuitry), 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 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.

[0112] For example, the structure of a complete optical receiving system can be shown in FIG15 . Each microring detector in the optical detector can be connected to a transimpedance amplifier (TIA), which can be connected to an operational amplifier (AMP). Since the signal rate received by each microring detector is relatively low (typically 8 Gbits per second (bps) to 56 Gbps), the first photocurrent generated based on the optical signal with a relatively low 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 optical signal rate, thereby reducing latency and cost.

[0113] In summary, the WDM optical receiving array based on microring detectors can be a dense wavelength division multiplexing (DWDM) optical receiving array, which can achieve single-fiber high-capacity communication by integrating multiple 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 receive array can be integrated into a separate chip, or it can be integrated on the same chip with the transmitter array.

[0116] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware, or any combination thereof. When implemented using software, all or part of the embodiments may be implemented 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, all or part of the processes or functions described herein are generated. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions may be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via a wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) method. The computer-readable storage medium may 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 integrated therein. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a magnetic tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state drive).

[0117] In this application, the terms "first," "second," and the like are used to distinguish between identical or similar items having substantially the same function or effect. It should be understood that "first," "second," and "nth" do not have a logical or temporal dependency, nor do they limit the quantity or order of execution. It should also be understood that although the following description uses the terms "first," "second," and the like to describe various elements, these elements should not be limited by these terms. These terms are simply used to distinguish one element from another.

[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] In this application, the term "at least one" means one or more, and the term "plurality" means two or more. For example, "plurality of 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 terminology used in the description of the various examples herein is for the purpose of describing particular examples only and is 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" as used herein refers to and encompasses any and all possible combinations of one or more of the listed items. The term "and / or" describes an association between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A exists alone, A and B exist simultaneously, or B exists alone. Furthermore, the character " / " in this application generally indicates that the associated objects 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 [stated condition or event] is detected” may be interpreted to mean “upon determining ” or “in response to determining ” or “upon detecting [stated condition or event]” or “in response to detecting [stated condition or event],” depending on the context.

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