Dual-wavelength narrow-linewidth fiber laser based on F-P fiber ring filter

A dual-wavelength fiber laser with a narrow-linewidth, based on a P-F fiber filter has been proposed. Polarization-maintaining fiber Bragg grating (PM-FBG) and a F-P fiber filter are introduced based on the traditional fiber laser. PM-FBG is used as the wavelength selection device. The fiber F-P filter consists of two optical couplers and a section of un-pumped erbium-doped fiber (EDF). Due to the delay of cavity and the loss generated by the EDF, the filter has comb spectral response. The incorporation of the fiber F-P filter leads to the suppression of undesirable modes. At the room temperature, under 980 nm LD pumped, the maximum output of the two wavelengths is respectively −2.259 dBm and 0.568 dBm, with the 3-dB bandwidth separately 0.1 nm and 0.14 nm, realizing the narrow linewidth and dual-wavelength output.