In-Band OSNR Monitoring Using Spectral Analysis After Frequency Down-Conversion

Abstract—A novel method for simultaneous optical signal-to-noise ratio and chromatic dispersion monitoring in wavelength-division multiplexed 40-Gb/s systems is proposed and demonstrated. This technique has a fast response time of <10 ms, applicable to dynamically reconfigurable networks, and is able to simultaneously monitor multiple impairments across multiple channels. Index Terms—Chromatic dispersion (CD), optical signal-to-noise ratio (OSNR), single sideband (SSB). I