Open AccessComplex modulation and detection with directly modulated lasers
Author(s) -
Qian Hu,
Di Che,
Yifei Wang,
Yanqin Feng,
Qi Yang,
William Shieh
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.032809
Subject(s) - intensity modulation , optics , chirp , signal (programming language) , modulation (music) , phase modulation , intensity (physics) , laser , sensitivity (control systems) , phase (matter) , materials science , physics , phase noise , computer science , electronic engineering , acoustics , quantum mechanics , programming language , engineering
Due to the chirp effect, the modulation information is carried by both intensity and phase of the optical signal generated by a directly modulated laser (DML). Compared to the signal recovery based on intensity alone, the receiver sensitivity is significantly improved when phase is also involved for signal recovery. In this paper, we provide thorough analysis of two schemes to recover the directed modulated signal based on the combined information of intensity and phase. The intensity and phase combined recovery for polarization-division-multiplexed (PDM) directly modulated signal is demonstrated for the first time, achieving a data rate of 40 Gb/s over a transmission distance of 160 km. Compared with the conventional intensity-only recovery, the receiver sensitivity is improved by 5.5 dB and 10 dB respectively by using two intensity and phase combined recovery schemes.