Crossing-based optical spectrum analyzer
Abstract
We report the performance of an optical spectrum analyzer that determines the spectrum of the light source using only as primary data, the crossing locations {ti} of the interferogram s(t) with reference sinusoid r(t) = A cos(2πfrt). The sinusoid crossings (SC) {ti} are solutions to: s(t) − r(t) = 0.
We have demonstrated the performance of a SC-based spectrum analyzer, which determines the power spectrum of the light source using a newly developed procedure that is different from the one used previously. An SC detector is a nonlinear system and the new procedure will permit us to measure weak sigals using the phenomenon of stochastic resonance.
Our spectrum analyzer has a sampling distance of 7.19 nm and therefore a (theoretical) spectral resolution of 14.38 nm. In practice, the reflectance of the mirrors, the transmittance of the lenses and the spectral response of the photodetector limit the effective response of the optical spectrum analyzer.