Demonstration of Programmable In-Band OSNR Monitoring Using LCFBG With Commercial Thermal Printer Head

We proposed and experimentally demonstrated a programmable optical signal-to-noise ratio (OSNR) monitoring scheme by using linearly chirped fiber Bragg grating (LCFBG) and a commercial thermal printer head. For the coherent optical orthogonal frequency-division multiplexing (CO-OFDM) transmission system, the monitor's working wavelength can be flexibly software-controlled from 1530 to 1538 nm to support standard ITU-T grid or flex-grid operation. The linear OSNR monitoring range has been achieved from 9 to 26 dB for a 16-quadrature amplitude modulation (QAM) OFDM transmission system with negligible errors, respectively. Neither chromatic dispersion nor polarization mode dispersion affect the monitoring accuracy of our system.