High-performance detection method and device for receiving end of continuous variable quantum key distribution chip system
By splitting and multi-channel detection of local oscillator and signal light in the CV-QKD chip system, and then electrically coupled output, the problem of low linear saturation power of the photodetector is solved, the system performance is improved, and the implementation process is simplified. Reduces cost and noise impact.
Patent Information
- Application Number
- CN202411325696.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-23
- Publication Date
- 2024-12-20
AI Technical Summary
The existing CV-QKD chip system has low quantum detection performance at the receiving end due to the low linear saturation power of the photodetector, which is difficult to meet the requirements of high-optical amplification capabilities. Direct optimization of PD performance will increase cost and time periods, reduce bandwidth and introduce noise.
By beam splitting and multi-channel detection of local oscillator light and signal light, and electrically coupling output, the chip system's requirements for the linear saturation power of the photodetector are reduced and the system performance is improved.
It effectively improves the detection performance of the CV-QKD chip system, simplifies the implementation process, reduces time and economic costs, and avoids additional noise and bandwidth losses.
Smart Images
Figure CN119172070A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of quantum secure communication, and in particular relates to a high-performance detection method and device for a receiving end of a continuous variable quantum key distribution chip system. Background Art
[0002] Quantum secure communication technology represented by quantum key distribution (QKD) is the core of network security protection in the quantum information era. It plays a significant role and significance in ensuring the bottom line of cryptographic security and enhancing the security defense capabilities of cyberspace. QKD technology mainly has two technical approaches: continuous variables and discrete variables. Among them, continuous variable quantum key distribution (CV-QKD) uses the canonical component of the quantum light field as the carrier of key information. The device is common to classical coherent optical communications, and the code rate is high under medium and short distance transmission conditions, which is very suitable for quantum metropolitan area network and access network applications.
[0003] In order to achieve large-scale deployment and application, it is urgently required that the CV-QKD system has the properties of low cost, high integration and high stability. Photonic chip integration technology is an important technical means to solve the above problems. In the CV-QKD system, improving the local oscillator optical power can effectively improve the optical amplification capability, thereby improving the detection capability of quantum signals. Therefore, in the local local oscillator CV-QKD system represented by high performance, in order to achieve sufficient optical amplification, the output optical power of the local oscillator laser at the receiving end is usually required to be above 10mW, and the power reaching the photodetector (PD) after coherent detection is about 2.5mW or more. Sometimes, in order to achieve higher optical amplification capabilities, the local oscillator laser output optical power is required to be higher. However, as the light intensity received by the PD increases, the detector response will no longer remain linear, which will directly lead to an increase in the excess noise of the CV-QKD system, seriously affecting the performance of the system.
[0004] For local oscillator CV-QKD systems based on discrete devices, the PD detection performance is good, and the linear working range can basically meet the requirements of local oscillator CV-QKD usage scenarios. For chip CV-QKD systems, the on-chip detectors (such as germanium silicon detectors) library devices provided by chip processing manufacturers will no longer maintain linearity when the optical power reaching the PD is above 2mW, making it difficult to meet the requirements of CV-QKD system use. The conventional solution is to optimize the performance of the on-chip PD to achieve higher linear saturation power, but this method has higher requirements for device optimization design and process processing difficulty, and higher costs and time cycles; on the other hand, achieving higher linear saturation power generally means reduced device bandwidth and increased dark current, which will also reduce the quantum detection performance of the CV-QKD receiver.
[0005] Therefore, how to improve the quantum detection performance at the receiving end is the core technical issue for improving the performance of the CV-QKD chip system. Summary of the invention
[0006] The purpose of the present invention is to address the problem of low quantum detection performance at the receiving end of the existing CV-QKD chip system due to the low linear saturation power of the photodetector. The present invention discloses a high-performance detection method and device at the receiving end of a continuous variable quantum key distribution chip system. The present invention can effectively reduce the chip system's requirements for the linear saturation power of the photodetector by splitting the local oscillator light and the signal light and performing multi-path detection, and then electrically coupling the output, thereby improving the system performance.
[0007] On the one hand, the purpose of the present invention is achieved by the following technical solutions:
[0008] A continuous variable quantum key distribution chip system receiving end detection device, the continuous variable quantum key distribution chip system receiving end detection device comprising:
[0009] Coupling module 1, used to couple the signal light output by the optical fiber channel to the CV-QKD receiving end chip;
[0010] A local oscillator light source module, outputting a local oscillator light signal to the chip coupling module 2;
[0011] Coupling module 2, used to couple the local oscillator light output by the local oscillator light source module to the CV-QKD receiving end chip;
[0012] The optical splitter module 1 splits the signal light in the chip into N paths, and mixes them with the N paths of optical signals split by the local oscillator light source respectively;
[0013] The optical splitter module 2 splits the local oscillator light in the chip into N paths, and mixes them coherently with the N paths of optical signals split from the signal light;
[0014] N frequency mixing modules, respectively receiving the optical signals output by the optical splitting module 1 and the optical splitting module 2, and used for coherently coupling one of the local oscillator lights after the beam splitting with one of the signal lights after the beam splitting;
[0015] 2N photoelectric detection modules, wherein every two photoelectric detection modules form a group, each of which is connected to one mixing module, wherein one photoelectric detection module is used to convert one optical signal coupled and outputted by the corresponding mixing module into an electrical signal, and the other photoelectric detection module is used to convert the other optical signal coupled and outputted by the corresponding mixing module into an electrical signal, and by loading a bias voltage opposite to that of another photoelectric detection module in the same group, the output electrical signal is opposite to that of another photoelectric detection module in the same group;
[0016] An electrical output module, used to couple and add the electrical signals output by each photoelectric detection module, and output them to an amplification circuit module outside the chip;
[0017] The amplification circuit module converts the photocurrent signal into a voltage signal and amplifies the weak signal and outputs it to the signal acquisition module;
[0018] Signal acquisition module realizes observation and sampling of voltage signals.
[0019] According to a preferred embodiment, the coupling module 1 and the coupling module 2 use end face coupling or grating coupling.
[0020] According to a preferred embodiment, the local oscillator light source module is input into the chip through coupling outside the chip, or is integrated into the chip through heterogeneous or heterogeneous integration.
[0021] According to a preferred embodiment, the splitting ratio of the splitting module 1 and the splitting module 2 is 50:50, or 10:90, or 30:70, or any other ratio, or the splitting module 1 and the splitting module 2 are splitting modules with adjustable splitting ratios.
[0022] According to a preferred embodiment, the signal light and the local oscillator light received by each mixing module have the same splitting ratio.
[0023] According to a preferred embodiment, two photoelectric detection modules under the same frequency mixing module implement signal subtraction by loading bias signals in opposite directions.
[0024] According to a preferred embodiment, the light splitting module, the frequency mixing module and the photoelectric detection module can form N-path detection, where N≥2.
[0025] According to a preferred embodiment, the CV-QKD chip module is a silicon photonic platform, or an indium phosphide platform, or a silicon nitride platform, or a lithium niobate platform, or a hybrid integration of various platforms.
[0026] On the other hand, the present invention also discloses:
[0027] A high-performance detection method for a continuous variable quantum key distribution chip system receiving end is disclosed, which completes high-performance detection of a continuous variable quantum key distribution chip system receiving end by adopting the above-mentioned continuous variable quantum key distribution chip system receiving end detection device.
[0028] The aforementioned main scheme of the present invention and its further options can be freely combined to form multiple schemes, all of which are schemes that can be adopted and claimed for protection by the present invention. After understanding the scheme of the present invention, those skilled in the art can understand that there are multiple combinations based on the prior art and common knowledge, all of which are technical schemes to be protected by the present invention, and they are not exhaustively listed here.
[0029] Beneficial effects of the present invention:
[0030] The present invention can effectively solve the problem of low quantum detection performance at the receiving end due to low PD linear saturation power in the existing CV-QKD chip system, and can effectively reduce the chip system's requirements for PD linear saturation power, thereby improving the overall detection performance of the system. Compared with the direct PD integrated device optimization method, the present invention is simpler, more feasible, and does not introduce additional noise and bandwidth loss, and requires less time and economic costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 It is a schematic diagram of the high-performance 2-way split-light detection structure of the CV-QKD chip receiving end of the present invention;
[0032] Figure 2 It is a schematic diagram of the high-performance multi-path light splitting detection structure of the CV-QKD chip receiving end of the present invention. DETAILED DESCRIPTION
[0033] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.
[0034] It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the terms "first", "second", "third", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "set", "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or it can be indirectly connected through an intermediate medium, and it can be the internal connection of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.
[0035] In addition, the present invention should be pointed out that, in the present invention, unless the specific structure, connection relationship, positional relationship, power source relationship, etc. are specifically written out, the structure, connection relationship, positional relationship, power source relationship, etc. involved in the present invention are all known by those skilled in the art on the basis of the prior art without creative work.
[0036] Example 1
[0037] refer to Figure 1 As shown, the figure shows a continuous variable quantum key distribution chip system receiving end detection device, the continuous variable quantum key distribution chip system receiving end detection device includes:
[0038] The coupling module 1 is used to couple the signal light output by the optical fiber channel to the CV-QKD receiving end chip.
[0039] The local oscillator light source module outputs the local oscillator light signal to the chip coupling module 2.
[0040] The coupling module 2 is used to couple the local oscillator light output by the local oscillator light source module to the CV-QKD receiving end chip.
[0041] The optical splitter module 1 splits the signal light in the chip into two paths, which are mixed with the two optical signals separated by the local oscillator light source.
[0042] The optical splitter module 2 splits the local oscillator light in the chip into two paths, which are coherently mixed with the two paths of optical signals split from the signal light.
[0043] Mixing module 1: used for coherently coupling one of the local oscillator lights after beam splitting with one of the signal lights after beam splitting.
[0044] Mixing module 2: used for coherently coupling another path of local oscillator light after beam splitting with another path of signal light after beam splitting.
[0045] The photoelectric detection module 1 converts one of the optical signals coupled and outputted by the mixing module 1 into an electrical signal.
[0046] The photoelectric detection module 2 converts the other optical signal coupled and output by the mixing module 1 into an electrical signal, and outputs an electrical signal opposite to that of the photoelectric detection module 1 by loading a bias voltage opposite to that of the photoelectric detection module 1 .
[0047] The photoelectric detection module 3 converts one of the optical signals coupled and output by the mixing module 2 into an electrical signal.
[0048] The photoelectric detection module 4 converts the other optical signal coupled and output by the mixing module 2 into an electrical signal, and outputs an electrical signal opposite to that of the photoelectric detection module 3 by loading a bias voltage opposite to that of the photoelectric detection module 3 .
[0049] The electrical output module couples and adds the electrical signals output by the photoelectric detection module 1, the photoelectric detection module 2, the photoelectric detection module 3, and the photoelectric detection module 4, and outputs them to the amplification circuit module outside the chip.
[0050] The amplification circuit module converts the photocurrent signal into a voltage signal and amplifies the weak signal and outputs it to the signal acquisition module.
[0051] Signal acquisition module realizes observation and sampling of voltage signals.
[0052] Furthermore, the coupling module may be end-face coupling or grating coupling.
[0053] Furthermore, the local oscillator light source module can be external to the chip through coupling input into the chip, or can be integrated inside the chip through heterogeneity or heterogeneity.
[0054] Furthermore, the beam splitting ratio of the beam splitting module may be 50:50, 10:90, 30:70 or any other ratio, and may also be a beam splitting module with a variable beam splitting ratio.
[0055] Furthermore, the splitting ratios of the signal light and the local oscillator light received by the mixing module should be the same, so as to achieve the best signal strength.
[0056] Furthermore, the two photoelectric detection modules under the same mixing module implement signal subtraction by loading bias signals in opposite directions.
[0057] Furthermore, the CV-QKD chip module can be a silicon photonic platform, an indium phosphide platform, a silicon nitride platform, a lithium niobate platform, etc., or a hybrid integration of various platforms.
[0058] Example 2
[0059] refer to Figure 2 As shown, the figure shows a continuous variable quantum key distribution chip system receiving end detection device, the continuous variable quantum key distribution chip system receiving end detection device includes:
[0060] The coupling module 1 is used to couple the signal light output by the optical fiber channel to the CV-QKD receiving end chip.
[0061] The local oscillator light source module outputs the local oscillator light signal to the chip coupling module 2.
[0062] The coupling module 2 is used to couple the local oscillator light output by the local oscillator light source module to the CV-QKD receiving end chip.
[0063] The optical splitter module 1 splits the signal light in the chip into N paths, and mixes them with the N paths of optical signals split by the local oscillator light source respectively.
[0064] The optical splitter module 2 splits the local oscillator light in the chip into N paths, and mixes them coherently with the N paths of optical signals split from the signal light.
[0065] The N frequency mixing modules receive the optical signals output by the optical splitting module 1 and the optical splitting module 2 respectively, and are used to coherently couple one of the local oscillator lights after the splitting with one of the signal lights after the splitting.
[0066] 2N photoelectric detection modules, where every two photoelectric detection modules form a group, are respectively connected to one mixing module, wherein one photoelectric detection module is used to convert one of the optical signals coupled and outputted by the corresponding mixing module into an electrical signal, and the other photoelectric detection module is used to convert the other optical signal coupled and outputted by the corresponding mixing module into an electrical signal, and by loading a bias voltage opposite to that of another photoelectric detection module in the same group, the output electrical signal is opposite to that of the other photoelectric detection module in the same group.
[0067] The electrical output module is used to couple and add the electrical signals output by each photoelectric detection module and output them to the amplification circuit module outside the chip.
[0068] The amplification circuit module converts the photocurrent signal into a voltage signal and amplifies the weak signal and outputs it to the signal acquisition module.
[0069] Signal acquisition module realizes observation and sampling of voltage signals.
[0070] Furthermore, the coupling module may be end-face coupling or grating coupling.
[0071] Furthermore, the local oscillator light source module can be external to the chip through coupling input into the chip, or can be integrated inside the chip through heterogeneity or heterogeneity.
[0072] Furthermore, the beam splitting ratio of the beam splitting module may be 50:50, 10:90, 30:70 or any other ratio, and may also be a beam splitting module with a variable beam splitting ratio.
[0073] Furthermore, the splitting ratios of the signal light and the local oscillator light received by the mixing module should be the same, so as to achieve the best signal strength.
[0074] Furthermore, the two photoelectric detection modules under the same mixing module implement signal subtraction by loading bias signals in opposite directions.
[0075] Furthermore, the light splitting module, the frequency mixing module and the photoelectric detection module can constitute N-channel (N≥2) detection to meet the requirements of quantum signal detection with high linear saturation light intensity.
[0076] Furthermore, the CV-QKD chip module can be a silicon photonic platform, an indium phosphide platform, a silicon nitride platform, a lithium niobate platform, etc., or a hybrid integration of various platforms.
[0077] The present invention can effectively reduce the chip system's requirement for the linear saturation power of the photodetector by splitting the local oscillator light and the signal light and performing multi-path detection, and then electrically coupling the output, thereby improving the system performance.
[0078] Thus, the problem of low quantum detection performance at the receiving end due to low PD linear saturation power in the existing CV-QKD chip system is effectively solved, and the chip system's requirements for PD linear saturation power can be effectively reduced, thereby improving the overall detection performance of the system. Compared with the direct PD integrated device optimization method, the present invention is simpler, more feasible, and does not introduce additional noise and bandwidth loss, and requires less time and economic costs.
[0079] Example 3
[0080] Based on Example 1 and Example 2, this embodiment also discloses a high-performance detection method for the receiving end of a continuous variable quantum key distribution chip system.
[0081] High-performance detection of the receiving end of the continuous variable quantum key distribution chip system is achieved by adopting the aforementioned continuous variable quantum key distribution chip system receiving end detection device.
[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A continuous variable quantum key distribution chip system receiving end detection device, characterized in that: The continuous variable quantum key distribution chip system receiving end detection device comprises: Coupling module 1, used to couple the signal light output by the optical fiber channel to the CV-QKD receiving end chip; A local oscillator light source module, outputting a local oscillator light signal to the chip coupling module 2; Coupling module 2, used to couple the local oscillator light output by the local oscillator light source module to the CV-QKD receiving end chip; The optical splitter module 1 splits the signal light in the chip into N paths, and mixes them with the N paths of optical signals split by the local oscillator light source respectively; The optical splitter module 2 splits the local oscillator light in the chip into N paths, and mixes them coherently with the N paths of optical signals split from the signal light; N frequency mixing modules, respectively receiving the optical signals output by the optical splitting module 1 and the optical splitting module 2, and used for coherently coupling one of the local oscillator lights after the beam splitting with one of the signal lights after the beam splitting; 2N photoelectric detection modules, wherein every two photoelectric detection modules form a group, each of which is connected to one mixing module, wherein one photoelectric detection module is used to convert one optical signal coupled and outputted by the corresponding mixing module into an electrical signal, and the other photoelectric detection module is used to convert the other optical signal coupled and outputted by the corresponding mixing module into an electrical signal, and by loading a bias voltage opposite to that of another photoelectric detection module in the same group, the output electrical signal is opposite to that of another photoelectric detection module in the same group; An electrical output module, used to couple and add the electrical signals output by each photoelectric detection module, and output them to an amplification circuit module outside the chip; The amplification circuit module converts the photocurrent signal into a voltage signal and amplifies the weak signal and outputs it to the signal acquisition module; Signal acquisition module realizes observation and sampling of voltage signals.
2. The continuous variable quantum key distribution chip system receiving end detection device according to claim 1, characterized in that: The coupling module 1 and the coupling module 2 adopt end face coupling or grating coupling.
3. The continuous variable quantum key distribution chip system receiving end detection device according to claim 1, characterized in that: The local oscillator light source module is input into the chip through coupling outside the chip, or is integrated into the chip through heterogeneity or heterogeneity.
4. The continuous variable quantum key distribution chip system receiving end detection device according to claim 1, characterized in that: The beam splitting ratio of the beam splitting module 1 and the beam splitting module 2 is 50:50, or 10:90, or 30:70, or any other ratio, or the beam splitting module 1 and the beam splitting module 2 are beam splitting modules whose beam splitting ratio can be changed and adjusted.
5. The continuous variable quantum key distribution chip system receiving end detection device according to claim 1, characterized in that: The signal light and local oscillator light received by each mixing module have the same splitting ratio.
6. The continuous variable quantum key distribution chip system receiving end detection device according to claim 1, characterized in that: The two photoelectric detection modules under the same mixing module achieve signal subtraction by loading bias signals in opposite directions.
7. The continuous variable quantum key distribution chip system receiving end detection device according to claim 1, characterized in that: The light splitting module, the frequency mixing module and the photoelectric detection module can form N-way detection, where N≥2.
8. The continuous variable quantum key distribution chip system receiving end detection device according to claim 1, characterized in that: The CV-QKD chip module is a silicon photonics platform, an indium phosphide platform, a silicon nitride platform, a lithium niobate platform, or a hybrid integration of various platforms.
9. A high-performance detection method for a continuous variable quantum key distribution chip system receiving end, characterized in that: High-performance detection of the receiving end of a continuous variable quantum key distribution chip system is achieved by using the continuous variable quantum key distribution chip system receiving end detection device as described in claims 1 to 8.