Single-mode fiber coupling with a M-SPGD algorithm for long-range quantum communications

• URL: http://arxiv.org/abs/2012.04394v1
• Date: Tue, 8 Dec 2020 12:16:55 GMT
• Title: Single-mode fiber coupling with a M-SPGD algorithm for long-range quantum communications
• Authors: Kui-Xing Yang, Maimaiti Abulizi, Yu-Huai Li, Bo-Yang Zhang, Shuang-Lin Li, Wei-Yue Liu, Juan Yin, Yuan Cao, Ji-Gang Ren and Cheng-Zhi Peng
• Abstract summary: Single-mode fiber coupling is important for improving signal-to-noise ratio of daylight quantum key distribution (QKD) We develop a single-mode receiver with an adaptive optics (AO) system based on a modal version of the parallel descent algorithm. Under strong atmospheric turbulence, the M-SPGD AO system obtains about 3.7 dB in the single-mode fiber coupling efficiency and a significant suppression of fluctuation.
• Score: 4.329318122553747
• License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/
• Abstract: Satellite-based quantum communication is a promising approach for realizing global-scale quantum networks. For free-space quantum channel, single-mode fiber coupling is particularly important for improving signal-to-noise ratio of daylight quantum key distribution (QKD) and compatibility with standard fiber-based QKD. However, achieving a highly efficient and stable single-mode coupling efficiency under strong atmospheric turbulence remains experimentally challenging. Here, we develop a single-mode receiver with an adaptive optics (AO) system based on a modal version of the stochastic parallel gradient descent (M-SPGD) algorithm and test its performance over an 8 km urban terrestrial free-space channel. Under strong atmospheric turbulence, the M-SPGD AO system obtains an improvement of about 3.7 dB in the single-mode fiber coupling efficiency and a significant suppression of fluctuation, which can find its applications in free-space long-range quantum communications.

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