[1] Mehandiratta G, Kaler R S, Kaur G et al. Transmission analysis of 112 Gbps dual polarization QPSK /16QAM using coherent receiver with digital signal processing[C]∥2018 International Conference on Intelligent Circuits and Systems (ICICS), April 19-20, 2018, Phagwara, India., 87-92(2018).

[2] Pradhan S, Patnaik B, Panigrahy R et al. DP-QPSK based 400 Gbps/channel fiber optic DWDM system[C]∥2018 IEEE 5th International Conference on Engineering Technologies and Applied Sciences (ICETAS), November 22-23, 2018, Bangkok, Thailand., 1-5(2018).

[3] Gao D R, Li T L, Sun Y et al. Latest developments and trends of space laser communication[J]. Chinese Optics, 11, 901-913(2018).

[4] Zheng D H, Li Y, Zhou H H et al. Performance enhancement of free-space optical communications under atmospheric turbulence using modes diversity coherent receipt[J]. Optics Express, 26, 28879-28890(2018). http://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-22-28879

[5] Li S H, Chen X M, Ni G Q et al. Highly precise ground certification system of satellite laser communication[J]. Optics and Precision Engineering, 25, 1149-1158(2017).

[6] Toyoshima M, Fuse T, Kolev D R et al. Current status of research and development on space laser communications technologies and future plans in NICT[C]∥2015 IEEE International Conference on Space Optical Systems and Applications (ICSOS), October 26-28, 2015, New Orleans, LA, USA., 1-5(2015).

[7] Yu X N, Tong S F, Dong Y et al. Single beam tracking subsystem of space laser communication network[J]. Optics and Precision Engineering, 22, 3348-3353(2014).

[8] Böhmer K, Gregory M, Heine F et al. Laser communication terminals for the European data relay system[J]. Proceedings of the SPIE, 8246, 82460D(2012). http://spie.org/Publications/Proceedings/Paper/10.1117/12.906798

[9] [9] ZechH, HeineF, MotzigembaM, et al.Laser communication terminals for data relay applications: todays status and future developments[C]∥2017 IEEE International Conference on Space Optical Systems and Applications (ICSOS), November 14-16, 2017, Naha, Japan. New York: IEEE Press, 2017: 193- 198.

[10] Geisler D J. Modem module development for NASA’s orion spacecraft: achieving FSO communications over lunar distances. [C]∥Optical Fiber Communication Conference (OFC) 2020, San Diego, California. Washington, D.C.: OSA, 1-3(2020).

[11] Arikawa M, Ito T. Performance of mode diversity reception of a polarization-division-multiplexed signal for free-space optical communication under atmospheric turbulence[J]. Optics Express, 26, 28263-28276(2018). http://www.researchgate.net/publication/328325090_Performance_of_mode_diversity_reception_of_a_polarization-division-multiplexed_signal_for_free-space_optical_communication_under_atmospheric_turbulence

[12] Song H Q, Li L, Pang K et al. Demonstration of enhanced tolerance to turbulence and misalignment of a 10-Gbit/s QPSK free-space optical link by utilizing two aperture pairs combined with detecting multiple modes. [C]∥Optical Fiber Communication Conference 2019, March 3-7, 2019, San Diego, California, United States. Washington, D.C.: OSA, Th2A, 41(2019).

[13] Zhang J, Qiu Q. High-precision fourth power carrier phase recovery algorithm[J]. Laser & Optoelectronics Progress, 56, 130604(2019).

[14] Lin Z Y, Yang Y F, Xiang Q et al. Adaptive carrier phase recovery algorithm for probabilistically shaped signals[J]. Acta Optica Sinica, 40, 2306001(2020).

[15] Li Y Z, Wang M G, Guo Y X et al. Dual-polarization carrier phase recovery algorithm based on simplified extended Kalman filter[J]. Acta Optica Sinica, 39, 1106005(2019).

[16] Viterbi A. Nonlinear estimation of PSK-modulated carrier phase with application to burst digital transmission[J]. IEEE Transactions on Information Theory, 29, 543-551(1983).

[17] Pfau T, Hoffmann S, Noe R et al. Hardware-efficient coherent digital receiver concept with feedforward carrier recovery for M-QAM constellations[J]. Journal of Lightwave Technology, 27, 989-999(2009). http://www.osapublishing.org/jlt/abstract.cfm?uri=jlt-27-8-989

[18] Cao Y W, Yu S, Shen J et al. Frequency estimation for optical coherent MPSK system without removing modulated data phase[J]. IEEE Photonics Technology Letters, 22, 691-693(2010).

[19] Boucheret M L, Mortensen I, Favaro H et al. A new algorithm for nonlinear estimation of PSK-modulated carrier phase. [C]∥3rd European Conference on Satellite Communications-ECSC-3, 1993, November 2-4, 1993, Manchester, UK. London: IET, 155-159(1993).

[20] Hoffmann S, Peveling R, Pfau T et al. Multiplier-free real-time phase tracking for coherent QPSK receivers[J]. IEEE Photonics Technology Letters, 21, 137-139(2009). http://ieeexplore.ieee.org/document/4685852

[21] Wang Y, Wu Z Y, Li X L et al. Non-data-aided cycle slip self-correcting carrier phase estimation for QPSK modulation format of coherent wireless optical communication system[J]. IEEE Access, 7, 110451-110462(2019). http://ieeexplore.ieee.org/document/8793073

[22] Rozental V N, Kong D M, Foo B et al. Cycle-slip-less low-complexity phase recovery algorithm for coherent optical receivers[J]. Optics Letters, 42, 3554-3557(2017). http://europepmc.org/abstract/MED/28914900

[23] Hoffmann S, Wördehoff C, Bermani A A et al. Hardware-efficient phase estimation for digital coherent transmission with star constellation QAM[J]. IEEE Photonics Journal, 2, 174-180(2010). http://ieeexplore.ieee.org/document/5427087

[24] Li Y, Wu M W, Du X W et al. A refinement to the Viterbi-Viterbi carrier phase estimator and an extension to the case with a Wiener carrier phase process[J]. IEEE Access, 7, 78170-78184(2019). http://ieeexplore.ieee.org/document/8735852/

[25] Tao Z N, Li L, Isomura A et al. Multiplier-free phase recovery for optical coherent receivers. [C]∥Optical Fiber Communication Conference 2008, February 24-28, 2008, San Diego, California, United States. Washington, D.C.: OSA, OWT2(2008).