Time division multiplexing optical path insertion loss measuring device and method

Abstract

According to the time division multiplexing optical path insertion loss measuring device and method provided by the invention, conventional instruments such as an optical power meter, a polarization analyzer and a photoelectric probe can be utilized, and the insertion loss of each path in a time division multiplexing optical path can be directly measured without participation of a single-photon detector and complicated measurement process and data processing; meanwhile, with the help of the device, when the device faces different light paths to be measured, instrument configuration does not need to be changed, and the device can adapt to the light paths with different delay differences. Therefore, the insertion loss of the time division multiplexing optical path can be measured efficiently and accurately by means of simple operation and low device cost.

Description

technical field [0001] The invention relates to the field of quantum secure communication, in particular to a time-division multiplexing optical path insertion loss measurement device and method. Background technique [0002] In quantum key distribution (QKD) systems based on polarization coding schemes, in order to avoid the security loopholes introduced by different quantum state detection efficiencies, many quantum key distribution systems have adopted time-division multiplexing design in the decoding optical path. After time-division multiplexing, the states enter the same single-photon detector for detection. [0003] In the decoding optical path based on time-division multiplexing, the time-division multiplexing process is realized by making different quantum states of the same base vector enter the same single-photon detector successively through two paths with different optical paths. [0004] For example in figure 1 In the time-division multiplexing decoding optic...

AI Technical Summary

Problems solved by technology

[0010] (1) This measurement method requires the use of single-photon detectors, but single-photon detectors are expensive, resulting in high costs

[0011] (2) The accuracy of the measurement results depends on the detection efficiency of the single-photon detector, and the precise measurement of the power at the single-photon level is difficult and technically complex, so it is often difficult to guarantee the measurement accuracy of the insertion loss of the time-division multiplexing optical path

Since the detection efficiency of single-photon detectors is usually related to the time domain, for gated single-photon detectors, the gating frequency is often required to be strictly consistent with the delay difference on the decoding optical path where the time-division multiplexing optical path to be tested is located, and the technical complexity is high. , so it will also make it difficult to guarantee the accuracy of the insertion loss measurement results of the time-division multiplexing optical path

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