A Novel Optical Vector Spectral Analysis Technique Employing a Limited Bandwidth Detector
01 January 2005
A new technique for obtaining frequency-dependent magnitude and phase information for an optical channel is presented that has application to optical monitoring, including dispersive effects, and for input to the control of adaptive optical filters. A test signal consisting of an optical comb of frequencies is generated, and the analysis circuit is based upon a tunable optical allpass filter and a receiver with bandwidth just large enough to accommodate the tone spacing, not the full channel spectral width. A method for generating a test signal spanning the spectrum of a modulated data signal without introducing inter-symbol interference is discussed.