Quantum key distribution codec silicon-based chip and matching method thereof

Abstract

The present application relates to a kind of quantum key distribution codec silicon-based chip and its matching method, belong to quantum key distribution technical field.The chip of the present application includes optical power distribution unit, photoelectric detector, micro resonant cavity and codec, photoelectric detector calculates input optical pulse repetition frequency, selects the codec matched with the optical pulse repetition frequency, controls the resonant wavelength of the micro resonant cavity connected to the selected encoder to be consistent with the wavelength of input optical pulse, input optical pulse to the branch where the codec is located, controls the resonant wavelength of the micro resonant cavity connected to the codec not matched with the optical pulse repetition frequency, so that the wavelength difference between the resonant wavelength and the wavelength of input optical pulse is greater than the set threshold value.The problem that the key cannot be effectively generated due to the different pulse repetition frequency matched between the transmitter encoder and the receiver decoder when different manufacturers or the same manufacturer different generations of QKD equipment are networked is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to a quantum key distribution encoding and decoding silicon-based chip and a matching method thereof, and belongs to the technical field of quantum key distribution. BACKGROUND

[0002] Quantum key distribution technology (QKD) can enable communication parties to securely share keys and is widely used in the field of quantum communication. In the prior art, optical quantum is encoded and decoded by various encoding methods such as polarization encoding and decoding, phase encoding and decoding, and time-phase encoding, that is, a light source emits pulsed light which is attenuated to the order of a single photon by an adjustable attenuator, enters an encoder for encoding and is output to a quantum channel, a receiving decoder receives the pulse for decoding, and then the key is formed after detection and basis matching. Improving the key generation efficiency has become an important direction for the development of QKD technology, and currently increasing the pulse repetition frequency of the light source is an effective method to improve the key generation efficiency of the communication parties. In the prior art, when the pulse repetition frequency of the light source is increased, the delay time of the delay line in the transmitting encoder and the receiving decoder needs to be matched, and at the same time, the modulation rate of the modulator also needs to be matched.

[0003] For QKD devices of different manufacturers or different generations of the same manufacturer, the encoders and decoders used are not consistent, and when the pulse repetition frequency of the light source is different, the encoding and decoding modules do not match the light source. For example, for phase encoding and time-phase encoding, the delay time of the delay line in the encoding module and the phase modulation rate of the modulator are different for light sources with different pulse repetition frequencies. When the transceiving devices at both ends of the network are composed of QKD devices of different manufacturers or different generations, the delay time in the encoding module and the delay time in the decoding module do not match, and the modulation rate of the encoding module and the modulation rate of the decoding module do not match, which leads to the problem that the key cannot be effectively generated. SUMMARY

[0004] The purpose of the present application is to provide a quantum key distribution encoding and decoding silicon-based chip and a matching method thereof, which solves the problem that when QKD devices of different manufacturers or different generations of the same manufacturer are used to form a network, the pulse repetition frequency of the transmitting encoder and the receiving decoder does not match, resulting in the problem that the key cannot be effectively generated.

[0005] To achieve the above-mentioned purpose, the scheme of the present application includes:

[0006] The application discloses a quantum key distribution encoding and decoding silicon-based chip, which comprises at least one optical power distribution unit, a photodetector, at least four micro resonant cavities and at least two encoders and decoders; one encoder is provided with two micro resonant cavities, one of which is connected with an input port of the encoder and used for receiving optical pulses input into the encoder, and the other is connected with an output port of the encoder and used for outputting optical pulse signals of the encoder; the first optical power distribution unit is connected with the photodetector and used for distributing part of the input optical pulses into the encoder through the input micro resonant cavity corresponding to the encoder matched with the optical pulse repetition frequency, and distributing another part into the photodetector; the photodetector is used for detecting the input light in real time and obtaining the optical pulse repetition frequency according to the detection result; the micro resonant cavity is used for adjusting the resonant wavelength to be consistent with the optical pulse wavelength when the optical pulse repetition frequency is matched with the encoder connected with the micro resonant cavity, and adjusting the resonant wavelength so that the resonant wavelength is greater than the optical pulse wavelength by a set threshold value when the optical pulse repetition frequency is not matched with the encoder connected with the micro resonant cavity.

[0007] The quantum key distribution encoding and decoding silicon-based chip comprises the optical power distribution unit, the photodetector, the micro resonant cavity and the encoder, the chip is simple and compact in structure, the optical pulse repetition frequency of the input light is detected according to the photodetector, the encoder matched with the optical pulse repetition frequency is selected, the resonant wavelength of the micro resonant cavity connected with the encoder is adjusted, the optical pulse is ensured to be input into the optical path, the resonant wavelength of the micro resonant cavity connected with the other encoders which are not matched is adjusted so that the resonant wavelength is greater than the optical pulse wavelength by a set threshold value, and the problem that the quantum key cannot be effectively generated due to the different matching pulse repetition frequencies between the transmitting end encoder and the receiving end decoder in the networking process of the quantum key distribution equipment of different manufacturers or different generations of the quantum key distribution equipment of the same manufacturer is solved.

[0008] Further, the optical power distribution unit comprises N (N is greater than or equal to 3) optical power distribution units, the optical power distribution units are connected in series through straight waveguides, the encoders are arranged outside the straight waveguides of adjacent two optical power distribution units in the second to Nth optical power distribution units in sequence, and the encoders are connected to the outside of the straight waveguides through the corresponding micro resonant cavities.

[0009] The application has the beneficial effects that the optical power distribution unit is multiple, the chip is compact in structure, the network scale of the optical distribution unit is expanded, and the matching of a larger optical pulse repetition frequency range can be realized.

[0010] Further, the optical power distribution unit has one optical power distribution unit connected with an input waveguide, the encoders are arranged inside the input waveguide and an output waveguide, the micro resonant cavity connected with the input port of the encoder is connected to the input waveguide, and the micro resonant cavity connected with the output port of the encoder is connected to the output waveguide.

[0011] Beneficial effects: when the optical power distribution unit has one, the optical power distribution unit is saved, and the space size of the chip and the manufacturing cost are saved.

[0012] Further, the straight waveguide connected to the second to Nth optical power distribution unit has two, and the codec and the micro resonant cavity are arranged on the outer side of each straight waveguide.

[0013] Beneficial effects: the straight waveguide connected to the second to Nth optical power distribution unit has two, and the codec and the micro resonant cavity are arranged on the outer side of each straight waveguide, the chip structure is simple and compact, and the space of the chip can be reasonably utilized, and the flexible distribution of optical power is realized through the codec and the micro resonant cavity.

[0014] Further, the optical power distribution unit is a 2x2 Mach-Zehnder interference structure.

[0015] Beneficial effects: the optical power distribution unit is a 2x2 Mach-Zehnder structure, and the optical power of two output ports can be controlled.

[0016] Further, the micro resonant cavity is a micro disk resonant cavity or a micro ring resonant cavity.

[0017] Beneficial effects: the micro resonant cavity is a micro disk resonant cavity or a micro ring resonant cavity, the micro disk resonant cavity changes the phase of light in the waveguide through the thermo-optic effect, the micro ring resonant cavity changes the phase of light in the waveguide below by applying voltage on the hot electrode to generate heat, thereby adjusting the resonant wavelength, and the two resonant cavity structures are simple and small, and the resonant wavelength can be well adjusted.

[0018] Further, when the photoelectric detector detects that the optical pulse repetition frequency changes, the currently working codec is stopped, the codec matched with the current optical pulse repetition frequency is started according to the current obtained optical pulse repetition frequency, the resonant wavelength of the micro resonant cavity coupled with the codec is controlled to be consistent with the current optical pulse wavelength, and the resonant wavelength of the micro resonant cavity connected to the codec not matched with the optical pulse repetition frequency is controlled to be greater than a set threshold value.

[0019] Beneficial effects: when the optical pulse repetition frequency changes, the current codec cannot encode and decode, the currently working codec is stopped, the codec matched with the current optical pulse repetition frequency is started according to the current obtained optical pulse repetition frequency, the optical pulse repetition frequency is calculated in real time, the micro resonant cavity is adjusted in real time, the codec that can be matched is selected, and the key effective generation is realized.

[0020] The quantum key distribution codec matching method of the application comprises the following steps:

[0021] 1) inputting an optical pulse, calculating a repetition frequency of the inputted optical pulse;

[0022] 2) according to the obtained optical pulse repetition frequency, selecting a codec matched with the optical pulse repetition frequency, and controlling a resonance wavelength of a micro resonant cavity connected with the selected encoder to be consistent with a wavelength of the inputted optical pulse, so as to input the optical pulse into a branch where the codec is located, and controlling a resonance wavelength of a micro resonant cavity connected with a codec not matched with the optical pulse repetition frequency to be deviated from the wavelength of the inputted optical pulse by more than a set threshold, wherein the codec is at least two.

[0023] Beneficial effects: the quantum key distribution codec matching method of the application calculates the repetition frequency of the inputted optical pulse according to the inputted optical pulse, selects a codec matched with the optical pulse repetition frequency, adjusts the resonance wavelength of the micro resonant cavity connected with the codec to ensure the optical pulse to be inputted into the optical path, and controls the resonance wavelength of the micro resonant cavity connected with the codec not matched with the optical pulse repetition frequency to be deviated from the wavelength of the inputted optical pulse by more than a set threshold, thereby solving the problem that the quantum key distribution equipment of different manufacturers or the quantum key distribution equipment of different generations of the same manufacturer cannot effectively generate the key due to the different pulse repetition frequencies matched between the transmitting end encoder and the receiving end decoder.

[0024] Further, the codec is provided with two micro resonant cavities, one of which is connected with the input port of the codec for inputting the optical pulse of the codec, and the other of which is connected with the output port of the codec for outputting the optical signal of the codec.

[0025] Beneficial effects: the codec is provided with two micro resonant cavities, and the resonance wavelength of the micro resonant cavity is adjusted to make the optical pulse to be inputted or not inputted into the optical path.

[0026] Further, when the repetition frequency of the inputted optical pulse changes, the currently working codec is stopped, the codec matched with the current obtained optical pulse repetition frequency is started, the resonance wavelength of the micro resonant cavity connected with the selected encoder is controlled to be consistent with the wavelength of the inputted optical pulse, and the resonance wavelength of the micro resonant cavity connected with the codec not matched with the optical pulse repetition frequency is controlled to be deviated from the wavelength of the inputted optical pulse by more than a set threshold.

[0027] Beneficial effects: when the optical pulse repetition frequency changes, the current codec cannot be encoded and decoded, the current working codec is stopped, the codec matched with the current obtained optical pulse repetition frequency is started, the optical pulse repetition frequency is calculated in real time, the micro resonant cavity is adjusted in real time, the codec that can be matched is selected, and the key effective generation is realized. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a chip architecture schematic diagram of the quantum key distribution codec chip embodiment in the application with multiple optical power distribution units;

[0029] Figure 2 is a matching flowchart of the quantum key distribution codec chip matching method embodiment in the application;

[0030] Figure 3 is a structure schematic diagram of the micro disk resonant cavity of the quantum key distribution codec chip embodiment in the application;

[0031] Figure 4 is a structure schematic diagram of the micro ring resonant cavity of the quantum key distribution codec chip embodiment in the application;

[0032] Figure 5 is a chip architecture schematic diagram of the quantum key distribution codec chip embodiment in the application with a single optical power distribution unit;

[0033] Figure 6 is a normalized transmission spectrum diagram of the micro ring resonant cavity in the quantum key distribution codec chip embodiment in the application. DETAILED DESCRIPTION

[0034] The application will be further described in detail below with reference to the drawings.

[0035] Quantum key distribution codec silicon-based chip embodiment:

[0036] As Figure 1 shown, a quantum key distribution codec silicon-based chip includes an optical power distribution unit, a photodetector, a micro resonant cavity, and a codec.

[0037] The optical power distribution unit, the photodetector, the micro resonant cavity, and the codec in the embodiment are all prepared on a silicon-on-insulator wafer.

[0038] The embodiment includes N optical power distribution units, and N can be 1 or N≥3.

[0039] Figure 1The optical power distribution units in the illustrated embodiment are N (N≥3), namely S1 to SN, the N optical power distribution units are connected in series through silicon waveguides, forming an optical power distribution network, the photodetector is connected with the first optical power distribution unit, and the codec is arranged outside the straight waveguide of adjacent two optical power distribution units among the second to Nth optical power distribution units and connected to the outside of the straight waveguide through the corresponding micro resonant cavity. Each codec is configured with two micro resonant cavities, one of which is connected with the input side of the codec to access the optical pulse of the codec, and the other of which is connected with the output side of the codec to output the optical signal of the codec. Specifically, the silicon straight waveguide can be one or two, and in this embodiment, the N optical power distribution units are connected in series through two silicon waveguides.

[0040] The N distribution units are all formed based on a 2×2 Mach-Zehnder (MZI) structure, and by controlling the phase difference of the two arms of the Mach-Zehnder, the arbitrary ratio distribution of optical power at the output port is realized, and the input light source can be distributed to the codec. The silicon waveguide structure satisfies TE mode transmission.

[0041] Specifically, at the transmitting end of the QKD system, the pulsed light emitted by the light source is input into the codec chip in this embodiment through the port In of the first optical power distribution unit S1, and the first optical power distribution unit S1 outputs the pulsed light to the port connected with the photodetector P1.

[0042] Meanwhile, the first optical power distribution unit S1 outputs the pulsed light to the input port of the first stage of the optical power distribution network, i.e. the input port of the second optical power distribution unit S2, and the power distribution of this port is at the level of single photon. The remaining power of the optical pulse is distributed to the photodetector P1, and the photodetector P1 detects the repetition frequency of the optical pulse in real time.

[0043] The photodetector P1 is connected with one output port of the first optical power distribution unit S1 through a silicon waveguide, and by the setting of the first optical power distribution unit S1, the pulsed light enters the photodetector P1, the photodetector P1 detects the received pulsed light in real time and calculates the pulse repetition frequency f.

[0044] Among them, each codec corresponds to a pulse repetition frequency f, and the pulse repetition frequencies of the N codecs (Q1-QN) are f1, f2, … fN respectively. n According to the pulse repetition frequency f i , the codec Qi matched with the pulse repetition frequency is selected to work. For example, according to the pulse repetition frequency f1, the codec Q1 matched with it is selected to work.

[0045] For example, when the pulse repetition frequency f1 is detected by the photodetector P1, the codec Q1 matched with the pulse repetition frequency f1 is selected to work. Figure 1As shown, the optical power distribution network in the embodiment further includes M (M=2xN) micro resonators and N codecs. The micro resonators include micro disk resonators and micro ring resonators. Figure 3 As shown, the micro disk resonator changes the phase of light in the waveguide through the thermo-optic effect. Specifically, the micro disk resonator waveguide is provided with a hybrid phase shifter device of thermo-optic phase shifter and electro-optic phase shifter. The electro-optic phase shifter adopts a carrier injection type PIN structure, which can quickly adjust the resonant wavelength. The thermo-optic modulator adopts a hot electrode structure, which can fine tune the resonant wavelength to compensate for the resonant wavelength drift caused by external temperature changes.

[0046] As shown, the micro ring resonator has a metal hot electrode above the waveguide. The phase of light in the waveguide below is changed by applying a voltage to the hot electrode to generate heat, thereby adjusting the resonant wavelength. P-type ion doping and N-type ion doping are performed on both sides of the waveguide to form a PIN junction, forming a carrier injection type electro-optic phase shifter structure. Figure 4

[0047] The codec can be a phase codec, a time-phase codec, a differential phase shift codec, and a coherent state single channel codec. The delay line in the codec is set to different time delays to correspond to different optical pulse repetition frequencies.

[0048] The first stage structure of the optical power distribution network includes four micro resonators R1, R2, R3, and R4 and two codecs Q1 and Q2. The first stage structure of the optical power distribution network is as follows:

[0049] The micro resonators R1 and R2 are placed outside a waveguide connected between the second optical power distribution unit S2 and the third optical power distribution unit S3, and form a coupling structure with the waveguide. The input waveguide of the codec Q1 is coupled to the micro resonator R1, and the output waveguide of the codec Q1 is coupled to the micro resonator R2. The resonant wavelengths of the micro resonators R1 and R2 are adjusted so that the resonant wavelengths of the micro resonators are the same as the wavelengths of the input optical pulses.

[0050] The micro resonators R3 and R4 are placed outside another waveguide connected between the second optical power distribution unit S2 and the third optical power distribution unit S3, and form a coupling structure with the waveguide. The micro resonator R3 is coupled to the input waveguide of the codec Q2, and the micro resonator R4 is coupled to the output waveguide of the codec Q2. The resonant wavelengths of the micro resonators R3 and R4 are adjusted so that the resonant wavelengths of the micro resonators are greater than a set threshold from the wavelengths of the optical pulses. Specifically, the resonant wavelengths and the input optical pulse wavelengths have a power difference greater than 0.9 in the normalized transmission spectrum corresponding to the two wavelengths (i.e., a 10 dB power drop). The corresponding wavelength difference is the threshold.

[0051] As shown,​Figure 6 In the shown embodiment, light enters from the input port 1 of the ring resonator, and when the wavelength of the input light is at the resonant wavelength of the resonator, the light is output from the output port 2. Figure 6 In the shown embodiment, when the normalized transmission power corresponding to the wavelength of the input light drops to 0.1, the difference between the wavelength at this time and the resonant wavelength of the resonator is set as a threshold value, and in this example, the threshold value corresponding to the microring resonator structure is 7.33 nm. When the actual wavelength difference is greater than the threshold value, light enters from the input port 1 of the ring resonator and is output from the output port 3. For the second to Nth level structures of the optical power distribution network, the positions of the micro resonators and the codec are the same as those of the first level structure. Among the entire chip optical power distribution network, the micro resonators can be selected as micro disk resonators or micro ring resonators, and the types of the two micro resonators configured by the codec of each level structure are the same. The working principle of the optical power distribution network is as follows:

[0052] In this embodiment, the output splitting ratio of the first optical power distribution unit S1 is set, and the single-photon-level light output is output to the second optical power distribution unit S2, and the remaining power of the light pulse is distributed to the photodetector P1 to detect the repetition frequency of the light pulse in real time. The output splitting ratio of the second optical power distribution unit S2 is set, and all the single-photon-level pulse light is coupled into the micro resonator R1. After entering the micro resonator R1, the resonant wavelengths of the micro resonators R1 and R2 are adjusted so that the resonant wavelength of the micro resonator is the same as the wavelength of the light pulse. The light pulse is coupled from the micro resonator R1 to the codec Q1, and after coding, the optical signal is coupled through the micro resonator R2 and returned to the waveguide of the optical power distribution network. By adjusting the third optical power distribution unit S3 to the Nth optical power distribution unit SN, the coded light pulse is directly output from the output port OUT of the chip in this embodiment.

[0053] When the photodetector P1 receives and calculates the pulse light of other frequencies (such as f2) at this time, the operation of the codec Q1 is stopped, and the operation of the codec Q2 is selected. The output splitting ratio of the second optical power distribution unit S2 is set so that all the optical power is output from the port connected between the second optical power distribution unit S2 and the micro resonator R3, and the resonant wavelengths of the micro resonators R3 and R4 are set so that the resonant wavelengths are the same as the wavelength of the pulse light. The light pulse is coupled into the codec Q2 through the micro resonator R3, and after coding, it is coupled back to the waveguide of the optical distribution network through R4, and finally, by adjusting the third optical power distribution unit S3 to the Nth optical power distribution unit SN, the coded light pulse is directly output from the output port OUT of the chip in this embodiment.

[0054] There is another structure for the quantum key distribution and coding silicon-based chip in this embodiment, as shown in Figure 5As shown, mainly includes a optical power distribution unit S, photodetector P, M (M = 2 x N) micro resonator R i-1 And R i-2 (i = 1 to M) and N codec Q. The embodiment in the above embodiment on the basis of the device saves optical power distribution unit S2 to SN M-1 optical power distribution unit.

[0055] Optical power distribution unit S1 end and photodetector P1 connected, while the other end through the silicon straight waveguide and micro resonator R i-1 Connection, micro resonator R i-1 And R i-2 Respectively placed in the two waveguide inside. Micro resonator R i-1 With the input waveguide of codec Qi constitutes a coupling structure, micro resonator R i-2 With the output waveguide of codec Qi constitutes a coupling structure. The working principle of the chip is as follows:

[0056] 1) optical pulse through the optical power distribution unit S1 port In input to the chip in the embodiment, adjust the optical power distribution unit S1 makes single photon order optical pulse input to the straight waveguide, the remaining power of optical pulse output to photodetector P1.

[0057] 2) photodetector P1 on the input optical pulse signal real-time detection, and calculate the optical pulse repetition frequency f i (i = 1, 2, … n), according to the obtained optical pulse repetition frequency, start and the pulse plane repetition frequency matching codec Qi (i = 1, 2, … n).

[0058] 3) control and codec Qi coupled micro resonator Ri-1 and Ri-2, make micro resonator Ri-1 and Ri-2 resonant wavelength and pulse wavelength consistent, the rest of the micro resonant cavity resonant wavelength and the wavelength difference between the optical pulse wavelength is greater than a set threshold.

[0059] 4) when the photodetector P1 detects the optical pulse repetition frequency changes, stop the current codec work, recalculate the optical pulse repetition frequency f x (x = 1, 2, … n, and x ≠ i), according to the obtained optical pulse repetition frequency, start and the pulse plane repetition frequency matching codec Qx (x = 1, 2, … n, and x ≠ i). Control and codec Qx coupled micro resonator Rx-1 and Rx-2, make micro resonator Rx-1 and Rx-2 resonant wavelength and pulse wavelength consistent, the rest of the micro resonant cavity resonant wavelength deviates from the optical pulse wavelength, the resonant wavelength and the wavelength difference between the optical pulse wavelength is greater than a set threshold.

[0060] Quantum key distribution codec matching method embodiment:

[0061] As Figure 2 The codec matching method of quantum key distribution is shown in the figure. Firstly, the repetition frequency of the input optical pulse is calculated. According to the obtained repetition frequency of the optical pulse, the codec working with the optical repetition frequency is selected. Secondly, the optical power distribution unit is controlled. The optical pulse is input to the codec branch. The resonance wavelength of the micro resonator connected with the selected codec is controlled to be the same as the pulse wavelength. The optical pulse is input to the branch where the codec is located. The resonance wavelength of the micro resonator connected with the codec which does not match the optical pulse repetition frequency is controlled to be greater than the set threshold value. The optical pulse can enter the codec smoothly, and the device codec function is realized.

[0062] When the repetition frequency of the optical pulse detected by the photodetector changes, the current codec stops working, and another codec which matches the pulse repetition frequency is started. The optical power distribution unit and the micro resonator are controlled to make the optical pulse enter the new codec until the key distribution work is completed. The specific implementation is described in detail in the quantum key distribution codec chip embodiment, which will not be repeated here.

Claims

1. A quantum key distribution codec silicon-based chip, characterized by, The application relates to a kind of optical pulse signal processing device, comprising at least one optical power distribution unit, photodetector, at least four micro resonators and at least two codecs;One codec is configured with two micro resonators, one is connected with the input port of the codec, for receiving the optical pulse input into the codec, the other is connected with the output port of the codec, for outputting the optical pulse signal of the codec, the first optical power distribution unit is connected with the photodetector, for distributing part of the input optical pulse into the codec through the input micro resonator corresponding to the codec matching the optical pulse repetition frequency, and the other part is distributed into the photodetector;The photodetector is used to detect the input light in real time and obtain the repetition frequency of the optical pulse according to the detection result;The micro resonator is used to adjust the resonance wavelength to be consistent with the optical pulse wavelength when the optical pulse repetition frequency matches the codec connected with the micro resonator, and adjust the resonance wavelength so that the resonance wavelength is greater than the set threshold value from the optical pulse wavelength when the optical pulse repetition frequency does not match the codec connected with the micro resonator.

2. The quantum key distribution codec silicon-based chip of claim 1, wherein, The optical power distribution unit comprises N, N>=3, each optical power distribution unit is connected in series through straight waveguide, and the codec is arranged outside the straight waveguide of adjacent two optical power distribution units in the second to Nth optical power distribution units in sequence, and the codec is connected to the outside of the straight waveguide through the corresponding micro resonator.

3. The quantum key distribution codec silicon-based chip of claim 1, wherein, The optical power distribution unit has one, which is connected with the input waveguide, and the codec is arranged inside the input waveguide and the output waveguide, the micro resonator connected with the input port of the codec is connected to the input waveguide, and the micro resonator connected with the output port of the codec is connected to the output waveguide.

4. The quantum key distribution codec silicon-based chip of claim 2, wherein, The straight waveguide connected with the second to Nth optical power distribution units has two, and the codec and the corresponding micro resonator are arranged outside each straight waveguide.

5. The quantum key distribution codec silicon-based chip according to claim 2 or 3, wherein, The optical power distribution unit is a 2*2 Mach-Zehnder interference structure.

6. The quantum key distribution codec silicon-based chip according to claim 2 or 3, wherein, The micro resonator is a micro disk resonator or a micro ring resonator.

7. The quantum key distribution codec silicon-based chip according to claim 2 or 3, wherein, When the photodetector detects that the optical pulse repetition frequency changes, stop the currently working codec, start the codec matching the current optical pulse repetition frequency according to the current optical pulse repetition frequency, control the micro resonator coupled with the codec to make the resonance wavelength consistent with the current optical pulse wavelength, and control the resonance wavelength of the micro resonator connected with the codec not matching the optical pulse repetition frequency to be greater than the set threshold value from the wavelength of the input optical pulse.

8. A codec matching method of quantum key distribution, characterized by, The method comprises the following steps: 1) input optical pulse, and calculate the repetition frequency of the input optical pulse; 2) select the codec matching the optical pulse repetition frequency according to the obtained optical pulse repetition frequency, control the resonance wavelength of the micro resonator connected with the selected codec to be consistent with the wavelength of the input optical pulse, input the optical pulse into the branch where the codec is located, control the resonance wavelength of the micro resonator connected with the codec not matching the optical pulse repetition frequency to be greater than the set threshold value from the wavelength of the input optical pulse, and the codec is at least two. The codec is configured with two micro resonant cavities, one connected with the input port of the codec for accessing optical pulses of the codec, and the other connected with the output port of the codec for outputting optical signals of the codec.

9. The QKD codec matching method of claim 8, wherein, When the repetition frequency of the input optical pulses changes, the currently working codec is stopped, a codec matching the current repetition frequency of the optical pulses is started according to the current repetition frequency of the optical pulses, the resonant wavelength of the micro resonant cavity connected with the selected codec is controlled to be consistent with the wavelength of the input optical pulses, and the resonant wavelength of the micro resonant cavity connected with the codec not matching the repetition frequency of the optical pulses is controlled to have a wavelength difference with the wavelength of the input optical pulses greater than a set threshold.

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