Open AccessOSNR Monitoring for NRZ-PSK Signals Using Silicon Waveguide Two-Photon Absorption
Author(s) -
Ke Xu,
Hon Ki Tsang,
Gordon K. P. Lei,
Yi Min Chen,
Liang Wang,
Zhenzhou Cheng,
Xia Chen,
Chester Shu
Publication year - 2011
Publication title -
ieee photonics journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.725
H-Index - 73
eISSN - 1943-0655
pISSN - 1943-0647
DOI - 10.1109/jphot.2011.2170832
Subject(s) - engineered materials, dielectrics and plasmas , photonics and electrooptics
We study the use of two-photon absorption (TPA) in a silicon optical waveguide for measuring the optical signal-to-noise ratio (OSNR) of a nonreturn to zero phase-shift keying (NRZ-PSK) signal. The average photocurrent generated in the silicon waveguide increased by 70 nA (from 375 to 445 nA) for a change in OSNR from 28 to 6 dB and a constant total input power of 10 dBm. The nonresonant nature of the silicon waveguide TPA detector enables the simple measurement of OSNR over a continuous wide (>; 10 nm) wavelength range. For a 10-Gb/s NRZ-PSK signal, we show that when the residual dispersion in the optical signal exceeds 425 ps/nm, further increases in dispersion have little effect on the photocurrent. Thus, this TPA-based OSNR monitor can be used in practical systems with large dispersion.