The interference between two optical fields with nonzero spectral linewidths forms multiple moving space-charge fields inside photoconductive semiconductors that contain deep-level donors and traps. The dc components of the photocurrents generated can be expressed in terms of a convolution of a function that is characteristic of the crystal and the signal optical power spectrum when the other optical field (local oscillator) has a negligible linewidth. This permits the recovery of the optical signal power spectrum.
© 1995 Optical Society of America
Chen-Chia Wang and Frederic Davidson, "Optical spectrum analyzer of a new design," Opt. Lett. 20, 1035-1037 (1995)