Atmospheric Turbulence Optical Channel Shared Random Bit Extraction System

Abstract

The invention discloses an atmospheric turbulence optical channel shared random bit extraction system based on space diversity and time-division gating. The present invention randomly changes the space diversity sub-channel through which the laser signal emitted by the laser arrives at the photodetector by using time-division gating, so as to realize the random switching measurement of different sub-channels of space diversity; through random switching of different sub-channels of space diversity The measurement can make the sampling operation of the received optical signal under the condition that the sampling time interval is shorter than the autocorrelation time length of the fading of the atmospheric turbulent optical signal, and can also ensure that the sampling values ​​of the received optical signal obtained by two consecutive sampling measurements are approximately statistically independent. Therefore, when the random bit extraction rate is increased by reducing the sampling time interval of the computer acquisition system, the damage to the randomness of the extracted bit sequence can be alleviated by using the present invention.

Description

technical field [0001] The invention belongs to the technical field of information security, and relates to an atmospheric turbulent optical channel sharing random bit extraction system based on space diversity and time division gating. Background technique [0002] A Chinese invention patent with the application number of 201911247093.7 discloses a method for sharing random bits of atmospheric turbulent optical channels based on the spectral domain. It is mentioned in the background section of the description of the invention patent that, in general, in order to ensure that the extracted bit sequence has good randomness, the time interval between two consecutive sampling measurements is required to be greater than the autocorrelation time length of random optical signal fading. The Chinese invention patent with the application number of 201911247093.7 first transforms the fading time domain data of random optical signals obtained by continuous collection into the spectral d...

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Problems solved by technology

However, if the switching measurement is performed between different sub-channels, for example, in the case of n sub-channels, the received optical signal of the first sub-channel is measured at the first sampling time to obtain a sampling value of 1, and at the second sampling time the first sub-channel The received optical signals of two sub-channels are measured to obtain the sampling value 2, and so on. At the nth sampling time, the nth sub-channel received optical signal is measured to obtain the sampling value n, and then at the n+1 sampling time One sub-channel receives the optical signal to measure the sampling value n+1, and so on, the correlation between two adjacent sampling values ​​​​of the obtained sampling value sequence will be significantly smaller than the sampling obtained by simply measuring a single sub-channel Correlation between two adjacent sampled values ​​of a sequence of values

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