Fast polarization feedback control method and device

Abstract

The invention discloses a fast polarization feedback control method, which is used to realize the output of the control signal of the electric polarization controller according to the detection signal of the detector, and uses the condition of double threshold value inspection as the monitoring condition for switching from the polarization adjustment period to the coding period, That is, after the value F of the polarization evaluation function is measured once greater than the high threshold, the adjustment of the electric polarization controller is suspended, and then the specified number of times is continuously measured. If the results are all greater than the low threshold, the coding period is entered, wherein, I H (H), I H (V) are the readings of H and V detectors when measuring H light respectively, I P (P), I P (N) are the readings on the P and N detectors when measuring P light, respectively. The present invention also provides a device adopting the above control method. The invention has the following advantages: the realization does not require time delay, the electric polarization controller is continuously adjusted, and the efficiency of polarization compensation is improved.

Description

technical field [0001] The invention relates to the field of quantum communication, and more specifically relates to a fast polarization feedback control technology in the field of quantum communication. Background technique [0002] When using a microprocessor-based fast polarization feedback device for fast polarization feedback adjustment in the quantum communication process, this system takes DSP as an example, and the system device includes DSP (digital signal processor), FPGA (field programmable gate array), ADC ( Analog-to-Digital Converter), where DSP (Digital Signal Processor) and ADC (Analog-to-Digital Converter) are connected to FPGA (Field Programmable Gate Array), and the detector at the receiving end of the quantum key distribution device is connected to FPGA (Field Programmable Gate Array). array), and the output end of the DSP (Digital Signal Processor) is connected to the electric polarization controller at the receiving end of the quantum key distribution d...

AI Technical Summary

Problems solved by technology

[0003] The hysteresis and creep effects of extruded polarization controllers lead to a delay between two adjustments, making it difficult to achieve real-time compensation for rapidly changing polarization states in suspended optical cables

[0004] Many disturbances in the external field are extremely short and frequent. Some extremely short disturbances have little impact on the quantum key distribution device, but they will be detected by the existing algorithm and adjustment process and enter the adjustment cycle, so that the system will be in adjustment for a long time. state, the quantum key distribution device does not perform coding, which reduces work efficiency

In addition, it takes a long time to use the statistical value as the condition for judging whether the polarization feedback is completed. At this time, the polarization state has changed greatly, which will shorten the coding time before the next polarization adjustment.

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