Switchable and dual-wavelength self-Q-switched fiber laser based on a homemade Er/Yb double clad fiber and polarization maintaining fiber Bragg grating

We report an experimental study on the self-Q-switched operation of a linear cavity fiber laser based on a homemade Er/Yb double clad fiber as gain medium. The parameters of the self-Q-switched pulses depend on the active fiber length of 2, 3, and 4 m. With a maximum fiber length of 4 m, stable self-Q-switched pulses are obtained for the whole 976 nm pump range, with a minimum pulse duration of 1.24 µs and a maximum repetition rate of 92.57 kHz. When the fiber length is shortened to 2 m, the range of the pump power level, at which the self-Q-switched operation is attained, is significantly diminished. Besides, dual-wavelength and switchable single-wavelength laser operations of the fiber laser are achieved by using a polarization maintaining fiber Bragg grating as spectral filter. Laser wavelengths at 1536.7 and 1537.1 nm with a line-width of 0.4 nm are obtained. The maximum average output power for the Q-switched laser operating in the dual-wavelength regime is 472 mW.