Abstract

This paper develops a theoretical analysis of the tradeoff between carrier suppression and nonlinearities induced by optical IQ modulators in direct-detection subcarrier multiplexing systems. The tradeoff is obtained by examining the influence of the bias conditions of the modulator on the transmitted single side band signal. The frequency components in the electric field and the associated photocurrent at the output of the IQ modulator are derived mathematically. For any frequency plan, the optimum bias point can be identified by calculating the sensitivity gain for every subchannel. A setup composed of subcarriers located at multiples of the data rate ensures that the effects of intermodulation distortion are studied in the most suitable conditions. Experimental tests with up to five QPSK electrical subchannels are performed to verify the mathematical model and validate the predicted gains in sensitivity.

© 2014 IEEE

Impact of Band Rejection in Multichannel Broadband Subcarrier Multiplexing

Fernando A. Gutiérrez, Philip Perry, Frank Smyth, Andrew D. Ellis, and Liam P. Barry
J. Opt. Commun. Netw. 7(4) 248-252 (2015)

Modulation-format-free and automatic bias control for optical IQ modulators based on dither-correlation detection

Xiaolei Li, Lei Deng, Xiaoman Chen, Mengfan Cheng, Songnian Fu, Ming Tang, and Deming Liu
Opt. Express 25(8) 9333-9345 (2017)

Thermo-optic-based phase-shifter power dither for silicon IQ optical modulator bias-control technology

Honggang Chen, Bo Zhang, Leilei Hu, Yong Luo, Yi Hu, Xi Xiao, Xuerui Liang, Feng Li, and Linfei Gan
Opt. Express 27(15) 21546-21564 (2019)

Low-disturbance automatic bias point control for optical IQ modulator using digital chaotic waveform as dither signals

Hongyu Li, Xinghan Li, Chuanming Huang, Zhengran Li, Mengfan Cheng, Qi Yang, Ming Tang, Deming Liu, and Lei Deng
Opt. Express 31(13) 22179-22188 (2023)

Field trial of automatic bias control scheme for optical IQ modulator and demodulator with directly detected 112 Gb/s DQPSK Signal

Hwan Seok Chung, Sun Hyok Chang, Jong Hyun Lee, and Kwangjoon Kim
Opt. Express 21(21) 24962-24968 (2013)