[1] [1] W Shieh, H Bao, Y Tang. Coherent optical OFDM: Theory and design[J]. Opt Express, 2008, 16(2): 841-859.

[2] [2] Li Yongzhi, Xiao Jiangnan, Chen Ming, et al.. Experiment for optical orthogonal frequency division multiplexing system peak to average power ratio reduction with a new scheme using dummy subcarriers[J]. Acta Optica Sinica, 2013, 33(7): 0706020.

[3] [3] Lu Jia, Hu Yuanyuan, Liu Jianfei, et al.. All-optical wavelength conversion based on parallel dual-pump for polarization multiplexing OFDM signal in SOA[J]. Chinese J Lasers, 2015, 42(2): 0205005.

[4] [4] Wang Lingzi, Tang Xianfeng, Zhang Xiaoguang, et al.. Blind phase estimation algorithms based on decision-directed and decisionfeedback in PDM-CO-OFDM systems[J]. Chinese J Lasers, 2014, 41(3): 0305001.

[5] [5] Shieh W, Yi X, Ma Y, et al.. Coherent optical OFDM: Has its time come (Invited)[J]. Journal of Optical Networking, 2008, 7(3): 234-235.

[6] [6] Chen Ying. Channel Estimation Technology in PDM-CO-OFDM Systems[D]. Beijing: Beijing University of Posts and Telecommunications, 2011: 47-58.

[7] [7] Xu Yi, Li Li, Han Shan, et al.. Channel estimation for CO-OFDM system based on impulse response processed with window[J]. Journal of Optoelectronics·Laser, 2012, 23(10): 1901-1908.

[8] [8] Su Zhenzhen, Xu Yi, Dong Ying. Channel estimation based on analysis of phase noise compensation for CO-OFDM system[J]. Journal of Optoelectronics·Laser, 2013, 24(11): 2135-2142.

[9] [9] Liu X, Buchali F. Intra-symbol frequency-domain averaging based channel estimation for coherent optical OFDM[J]. Opt Express, 2008, 16(26): 21944-21957.

[10] [10] Liu J, Li J, Zeng X, et al.. Scattered pilot-based channel estimation with joint noise reduction for PDM-CO-OFDM system[J]. Optik, 2013, 124(22): 5422-5426.

[11] [11] Zeng Xiangye, Liu Jianfei, Wang Jingyi, et al.. An improved ISFA channel estimation algorithm[J]. Journal of Optoelectronics·Laser, 2014, 25(8): 1481-1487.