Passively Q-switched fiber laser with single and double wavelength switching based on parallel FBGs

Abstract We proposed a passively Q-switched fiber laser with switchable wavelength based on two parallel fiber Bragg gratings. By increasing the input power, a single wavelength with a center wavelength of 1545.63 nm and dual wavelengths with a center wavelength of 1545.63 nm and 1553.60 nm can be obtained respectively. The wavelength spacing of the dual wavelengths is 8.17 nm, and the maximum repetition frequency of Q-switching is 24.27 kHz, and the narrowest pulse width is 5.48 ms. The combination of parallel fiber grating and erbium-ytterbium co-doped fiber (EYDF) saturable absorber provides a simple and feasible method to obtain stable (single and double wavelength switching) passively Q-switched pulses.