Integrated in-band OSNR monitor based on planar lightwave circuit

We propose a novel integrated in-band optical signal-to-noise ratio (OSNR) monitor based on planar lightwave circuit (PLC) technology. We successfully demonstrate a 10-25 dB in-band OSNR measurement with errors of less than 0.6 dB. Since PLC type optical monitor is compact and simple, our proposed device would be excellent for performance monitoring in WDM networks.