Theoretical analysis of tunable wavelength conversion based on FWM in a semiconductor fiber ring laser

A comprehensive broad-band dynamic model of a tunable wavelength converter based on four-wave mixing (FWM) in a semiconductor fiber ring laser (SFRL) is presented. Critical factors, e.g., the material gain profile, the longitudinal variation of the optical field, the carrier density, photon density, and the broad-band spontaneous noise emission, are considered in the model. Therefore, the static and dynamic characteristics of this kind of wavelength converter can be predicted more accurately. By numerical simulation, the effects of the input signal power, injection current, the coupling coefficient of the output coupler, and the lasing wavelength on the conversion efficiency of the wavelength converter are investigated. Also, the optical pulse pattern, frequency chirp, and extinction ratio of the conjugate signal are evaluated. To widen the dynamic range of input signal power, an erbium-doped fiber amplifier (EDFA) is added into the SFRL. The characteristics of this tunable wavelength converter with an SFRL are investigated in detail.