A kind of multiwavelength erbium-doped fiber laser based on Lyot filter

A multiwavelength tunable ring-cavity erbium-doped fiber laser (EDFL) based on a Lyot filter was presented. For the proposed Lyot filter, a comb filter consisting of an EDF-polarization-maintaining fiber (EDF-PMF), a polarization controller (PC), and a circulator with four ports was used to suppress the mode competition. The light transmission direction was guaranteed by the circulator. For the proposed fiber laser, tunable single, dual, triple, quadruple, quintuple, sextuple, and septuple wavelengths were realized. A single-wavelength laser output with an optical signal-to-noise ratio (SNR) of up to 30.56 dB was realized, and a tuning range of 1590.54 nm to 1599.54 nm was achieved by tuning the PC. The stability of the single, dual, triple, and quadruple-wavelength center power fluctuations was less than 0.05 dB, 0.98 dB, 5.07 dB, and 7.71 dB respectively. When the laser was operated in the multiwavelength condition, the SNR was more than 20.97 dB. The proposed erbium-doped fiber laser is suitable for fiber-sensing system applications.