Femtosecond laser-inscribed polarization-maintaining fiber Bragg grating using line-by-line technique for generating wavelength-switchable erbium-doped fiber lasers

Abstract

In this study, a polarization-maintaining fiber Bragg grating (PM-FBG) was inscribed by a femtosecond laser using a line-by-line method through fiber coating and used as a wavelength selector for a wavelength-switchable erbium-doped fiber laser (EDFL). The PM-FBG period was 1.075 μm, and the grating length was 3200 μm. For the proposed EDFL, the lasing threshold was 64 mW, and switchable lasing emissions with stable single and dual wavelengths were realized by adjusting a polarization controller. For the experiments, different single-wavelength switchable lasers with scope values of 1563.34–1564.02 nm were generated, six dual-wavelength lasers were obtained, and a triple-wavelength laser output was realized. The power fluctuations of the single- and dual-wavelength lasers were lower than 0.331 and 0.682 dB, respectively, over a 25 min monitoring time.