“…Multi-wavelength erbium-doped fiber lasers (EDFLs) have attracted intensive interest due to their potential application in wavelength division multiplexed (WDM) fiber-communication systems, optical fiber sensors, optical instrument testing and THz generation. Various methods have been employed to realize room-temperature multi-wavelength fiber lasers such as introducing four-wave mixing in nonlinear fibers [1], exploiting Brillouin-Raman or Brillouin-erbium fiber lasers [2,3], utilizing the polarization hole burning effect in gain media [4] or a frequency-shifted feedback technique in a laser cavity [5], employing high nonlinear fibers [6,7] and so forth. On the other hand, to attain multi-wavelength operation, a multi-channel filter should usually be used, including a fiber Bragg grating based Fabry-Perot (FP) filter [8], a twin-core fiber-based Mach-Zehnder interferometer [9], Sagnac loop mirrors with polarization-maintaining fiber (PMF [10]), or a birefringence fiber filter [11].…”