title: Multi-wavelength in-band OSNR monitor based on Lyot-Sagnac interferometer.
abstract: A novel in-band OSNR monitor is proposed and experimentally demonstrated for WDM signal. By using a Lyot-Sagnac interferometer, the monitor realized OSNR measurement from 7.5~25 dB (within an accuracy of ± 0.5 dB) for 4-channel 40 Gbaud NRZ-QPSK signals, without requirement for prior knowledge of the noise-free coherence properties of signal. Further investigation proved that this OSNR monitor had high tolerance to chromatic dispersion (0~1152 ps/nm), first-order polarization mode dispersion (0~100 ps), and polarized noise. Moreover, the monitor worked very well even with input optical power as low as -8.24 dBm, and also worked in in C-band. Theoretical analysis and experimental results prove that it is capable of measuring OSNR for polarization-division-multiplexing signals.
authors.forename: Jifang
authors.initials: J
authors.lastname: Qiu
authors.forename: Zhuili
authors.initials: Z
authors.lastname: Huang
authors.forename: Bo
authors.initials: B
authors.lastname: Yuan
authors.forename: Na
authors.initials: N
authors.lastname: An
authors.forename: Deming
authors.initials: D
authors.lastname: Kong
authors.forename: Jian
authors.initials: J
authors.lastname: Wu