A dual-wavelength erbium-doped fiber ring laser was designed and investigated experimentally so as to supply an ideal source for the dense wavelength division multiplexing (DWDM) fiber communication and fiber sensing system. The fiber laser contains a tunable optical filter constructed with only one fiber Bragg grating (FBG) and two 3dB couplers. Combining with the polarization hole-burning effect of multi-mode fiber, a tunable dual-wavelength laser output can be obtained by changing the polarization of laser system. The experimental results show that, single- and dual-wavelength laser output can be obtained while tuning the polarization and the maximum differential wavelength of the laser output can reach up to 4.692nm. The laser mode-hopping phenomenon can be effectively suppressed by introducing a section of multi-mode fiber.
