Investigation of room-temperature multiwavelength fiber-ring laser that incorporates an SOA-based phase modulator in the laser cavity

Abstract

A theoretical and experimental study of a multiwavelength fiber-ring laser that incorporates a semiconductor optical amplifier (SOA) in the laser cavity as a phase modulator to suppress the homogeneous line broadening is presented. The analysis reveals that the phase shift introduced by the SOA-based phase modulator is more significant than that formed using a LiNbO 3 phase modulator, which leads to a better suppression of the homogeneous line broadening. Multiwavelength lasing with small wavelength spacing and improved stability at room temperature is achieved. A fiber-ring laser based on the proposed approach is implemented. Stable multiwavelength operation with up to 26 wavelengths and wavelength spacing as small as 0.19 nm at room temperature is demonstrated.Index Terms-Erbium-doped fiber (EDF), fiber laser, homogeneous line broadening, multiwavelength, phase modulation, semiconductor optical amplifier (SOA).