Gain Dependent Optimum Pulse Generation Rates of a Hybrid-Type Actively and Passively Mode-Locked Fiber Laser

Abstract

We have experimentally observed and theoretically analyzed the gain dependent optimum repetition rates of a hybrid-type active and passive mode locked laser pulses in an erbium-doped fiber laser of the figureof -eight geometry by utilizing a nonlinear amplifier loop mirror (NALM) as a saturable absorber and a directional-coupler type electro-optic modulator as an active mode locker. Transform-limited modelocked pulses of about 10 ps width were obtained at repetition rates which correspond to harmonics of the cavity fundamental frequency and depend on the optical amplifier gain in the NALM. 2 Kyong Hon Kim et al. ETRI Journal, volume 18, number 1, April 1996 I. INTRODUCTION Technology of ultrashort pulse generation with mode-locked erbium-doped fiber lasers (EDFLs) at the communication wavelength of 1.55 #m has rapidly advanced in recent years. Especially passive mode-locking schemes of the EDFLs in the figure-of-eight geometry with a nonlinear amplified loop mirror (NALM) or in the r...