Method and apparatus for fast polarization feedback control

Abstract

A method for fast polarization feedback control is disclosed. According to the detection signal of the detector, the control signal output of the electric polarization controller is realized, using the condition of the double threshold test as the monitoring condition of switching from the polarization adjustment period to the coded period, that is, when the value F of the primary polarization evaluation function is greater than the high threshold value, the adjustment of that electric polarization control is suspended, and then the specified number of times is continuously measured, if the results are greater than the low threshold, the encoding period is entered(shown in the description), wherein, IH (H) and IH (V) are the readings of H and V detectors when H light is measured, and IP (P) and IP (N) are the readings of P and N detectors when P light is measured. The invention also provides a device adopting the control method. The invention has the advantages that no delay is required, 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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