Patent ID: 7391970
Filing Date: 2008-06-24
Classification: H04B,H04J

Abstract:
1. An apparatus for monitoring optical signal-to-noise ratio (OSNR), comprising: an optical circulator guiding an input optical signal to a specified output trajectory; a tunable optical filter (TOF) receiving said optical signal output from said optical circulator, and then outputting a filtered optical signal after performing a first-pass filtering on said optical signal; a dithering signal; a dithered reflector receiving and dithering said single-pass filtered optical signal according to said dithering signal, and then outputting a dithered signal and a reflected dithered signal; and two photodiodes being a first photodiode and a second photodiode, said first photodiode receives said dithered signal and measures signal power; wherein said TOF receives said reflected dithered optical signal, and then outputs a double-pass filtered optical signal after performing a second-pass filtering on said reflected dithered optical signal, said optical circulator guides said double-pass filtered optical signal from said TOF to a specified output trajectory, said second photodiode receives said double-pass filtered optical signal from said optical circulator and measures noise power.