C+L band Erbium-doped fiber laser based on FBG fabricated by femtosecond laser

A switchable and stable single- and dual-wavelength C+L band Erbium-doped fiber laser based on FBG array fabricated by femtosecond laser was proposed and experimentally demonstrated. Fiber grating period of 538, 542, 547 nm was realized on polyimide fiber core through fiber protection and cladding by femtosecond laser, grating length was 3 000 m, and reflection spectrum of each FBG was 1 555.5, 1 569.6, 1 583.8 nm, respectively; the length of 3 m C-band Erbium-doped fiber and 10 m L-band were used as the gain medium, and the proposed fiber laser was composed of gain medium, pump source, FBG, PC and broadband reflection mirror. In the experiment, the laser working threshold was 35 mW, through adjusting the polarization controller, a switchable single-wavelength of 1 555.4, 1 569, 1 583.2 nm laser was obtained, 3 dB linewidth was 0.05 nm, and SNR was more than 35 dB; The spectral stability of single-wavelength laser was tested in the experiment, and it was found that the power fluctuation of each single-wavelength laser was less than 0.98 dB over 10 min; by adjusting the polarization controller, the proposed fiber laser had the capability to produce switchable 1 569, 1 583.2 nm and 1 555.4, 1 569 nm dual-wavelength laser simultaneously, and the power shift was less than 1.14 dB and 4.48 dB, respectively over 10 min monitoring time.