PAM-8 IM/DD Transmission Based on Modified Lookup Table Nonlinear Predistortion

• Published in: IEEE photonics journal Vol. 10; no. 3; pp. 1 - 9
• Main Authors: Zhang, Jiao, Gou, Pengqi, Kong, Miao, Fang, Kaibo, Xiao, Jiangnan, Zhang, Qi, Xin, Xiangjun, Yu, Jianjun
• Format: Journal Article
• Language: English
• Published: IEEE 01-06-2018
• Subjects: Finite impulse response filters; Indexes; intensity modulation and direct detection (IM/DD); look-up table (LUT) nonlinear pre-distortion; Nonlinear optics; Optical attenuators; Optical distortion; Optical sensors; Pulse amplitude modulation (PAM); Table lookup
• ISSN: 1943-0655; 1943-0647
• DOI: 10.1109/JPHOT.2018.2828869

In this paper, a modified lookup table (LUT) nonlinear predistortion method is proposed. With the modified LUT method, the number of patterns and the computational complexity can be reduced by half with a similar system performance comparing with normal LUT. We experimentally demonstrate an 8-ary pulse amplitude modulation (PAM-8) intensity modulation and direct detection (IM/DD) transmission over 15-km fiber using a directly modulated laser (DML) based on modified LUT. Around 1-dB receiver sensitivity improvement at bit-error ratio of 3.8 × 10 -3 is achieved by adopting a modified LUT over 15-km fiber transmission at 2 Gbaud based on a commercial DML. In addition, we also experimentally demonstrate Mach-Zehnder modulator based 40 Gbaud PAM-8 IM/DD transmission under back-to-back case, about 1-dB receiver sensitivity can also be improved.