Single-tuning dual-pulse Er3+-doped Q-switched all-fiber laser

An all-fiber actively Q-switched Er³⁺-doped laser is presented based on magnetostriction modulation of a fiber Bragg gratings (FBGs). The laser employs a pair of FBGs as reflective mirrors, one of which is bonded to a magnetostrictive rod. The Q-factor of the cavity is controlled by tuning the Bragg wavelength of the grating when a magnetic field is applied to the magnetostrictive rod. During a single-tuning period, the dual pulses are acquired from the Q-switched laser due to the FBGs' reflective peaks twice coincident. Using a maximum pump power of 120 mW, Q-switch pulses of 1.2W and 0.6 W peak powers is obtained, with a laser pulse repetition rate of 4.4 kHz and 8.8 kHz.