LPFG modulator for fiber laser Q switching

Abstract

A Q-switched fiber laser with all-fiber configuration is proposed in which an all-fiber Q-switching modulator is developed based on the long period fiber grating. The fiber laser cavity comprises a pair of fiber Bragg gratings which are used to confine oscillation wavelength of the laser, gain fiber and a long period fiber grating based modulator. The long period fiber grating modulator is inserted in the laser cavity as Q-switching device, where the long period fiber grating modulator contains a long period fiber grating and an actuator, the initial resonance loss of the long period fiber grating is matched to the fiber Bragg grating wavelength. While the actuator applies stress to a section of the long period fiber grating, transmission spectrum of the long period fiber grating can be changed accordingly; Q-factor of the fiber laser cavity can be alternately modulated thereby.