Triple-wavelength EDF laser employing sampled fiber grating and PMF

A novel triple-wavelength erbium-doped fiber laser employing linear cavity structure was presented and demonstrated experimentally. Cavity mirrors of the laser were composed of two left and right Sagnac loops. Left loop was formed by a fiber coupler (FC) with power ratio of 50:50, a sampled fiber grating (SFG) and a three-ring-type polarization controller (PC). Two adjacent transmission peaks of the SFG had 0.3 nm wavelength spacing. Right loop consisted of a same FC and a length of panda-type polarization-maintaining fiber (PMF). The two loops had different transmission spectra. They formed a couple of comb filters to mutually produce the multiple wavelengths. After the PC was tuned to cause the PHB effect, the laser could output three kinds of different lasing lines including single-wavelength, dual-wavelength, and triple-wavelength. All of lasing lines had more than 33 dB optical signal-noise-ratio and less than 0.67 nm linewidth.