Title :
Generation of Coherent and Frequency-Lock Optical Subcarriers by Cascading Phase Modulators Driven by Sinusoidal Sources
Author :
Zhang, Junwen ; Yu, Jianjun ; Tao, Li ; Fang, Yuan ; Wang, Yiguang ; Shao, Yufeng ; Chi, Nan
Author_Institution :
Dept. of Commun. Sci. & Eng., Fudan Univ., Shanghai, China
Abstract :
A novel scheme to generate coherent and frequency-lock optical subcarriers is proposed and experimentally demonstrated. 53 subcarriers with 12.5 GHz spacing and less than 10 dB power fluctuation are generated by cascading two stages of phase modulators, which are driven by 25 and 12.5 GHz clock sources at different modulation depths, respectively. The modulation index and phase difference of two stage phase modulation are theoretically and experimentally investigated. The flattening spectrum of the optical subcarriers is achieved by optimizing the clock phase relationship among the RF driving sources at both stages.
Keywords :
channel spacing; light coherence; optical communication equipment; optical fibre communication; optical modulation; phase modulation; clock phase; coherent optical subcarriers; flattening spectrum; frequency 12.5 GHz; frequency 25 GHz; frequency-lock optical subcarriers; modulation depths; optical OFDM; phase difference; phase modulators; sinusoidal sources; Fluctuations; Frequency modulation; OFDM; Optical modulation; Phase modulation; Radio frequency; Coherent and frequency-lock subcarrier generation; optical OFDM; phase modulator; timing synchronization;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2012.2203096
