Investigation of pump light generation methods and precise all-optical FWM wavelength conversion for wavelength defragmentation

Abstract

This study investigates pump light generation methods for all-optical wavelength conversion systems using four-wave mixing in highly nonlinear fibers. The number of light sources, combination of sinusoidal signal frequency, and number of cascaded stages of LiNbO₃ phase modulators were compared. As a result, 13 flat optical combs with a 10-GHz frequency spacing were generated with three-stage modulators, and it was confirmed that the noise level of the pump was as small as the seed light source. In the wavelength conversion experiment, a bit error rate of <10^-10 for the converted signals was obtained in the case of the ±60-GHz shift from the original carrier pump lights.