Chinese Optics Letters, Vol. 18, Issue 9, 090602 (2020)
Digital-analog hybrid optical phase-lock loop for optical quadrature phase-shift keying
Shaowen Lu1,2,3,*, Yu Zhou1, Funan Zhu2,3, Jianfeng Sun1,2, Yan Yang3, Ren Zhu3, Shengnan Hu3, Xiaoxi Zhang3, Xiaolei Zhu1,2, Xia Hou2,3,**, and Weibiao Chen1,2
- 1Key Laboratory of Space Laser Communication and Detection Technology, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
- 2Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China
- 3Laboratory of Space Laser Engineering, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China
We analyze a feasible high-sensitivity homodyne coherent optical receiver for demodulating optical quadrature phase-shift keying (QPSK). A fourth-power phase-lock loop based on a digital look-up table is used. Considering the non-negligible loop delay, we optimize the loop natural frequency. Without error correction coding, a sensitivity of ?37 dBm/?35 dBm is achieved, while the bit error rate is below 10?9 at 2.5 Gbaud/5 Gbaud rate. For the QPSK communication system, the bit rate is twice the baud rate. The loop natural frequency is 0.647 Mrad/s, and the minimized steady-state phase-error standard deviation is 3.83°.
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