Room temperature multiwavelength erbium-doped fiber ring laser employing equivalent low frequency shift feedback

An effective method to implement room temperature operation of multiwavelength erbium-doped fiber ring laser (MW-EDFL) employing equivalent low frequency shift feedback (ELFSF) is presented. Simultaneous multiwavelength lasing with 0.5nm wavelength spacing is experimentally demonstrated by applying a sawtooth signal of the order of 10kHz to a phase modulator inserted in the ring cavity to prevent single-wavelength oscillation. A LiNbO3 multifunction chip of fiber gyro has been used as the phase modulator, the output coupler, and the polarizer of Lyot periodic filter. The MW-EDFL output is linearly polarization light that meets the requirement of external modulation for WDM applications.