Channel spacing tunable multiwavelength EDF laser based on single segmented polarization maintaining fiber Lyot-Sagnac loop filter

A channel-spacing tunable and switchable multiwavelength Erbium-doped fiber laser (MW-EDFL) operating at room temperature is studied using available experimental data. The multiwavelength generation is achieved mainly based on a single segmented polarization maintaining fiber (PMF) in Lyot-Sagnac loop filter (LSLF) and an all-fiber phase modulator. The channel space tuning is performed by means of a polarizer and the DC offset voltage of a Lithium-Niobate (LiNbO₃) amplitude modulator and multiwavelenth switching is performed using polarization controller, those are incorporated in the PMF-LSLF. It is found that discrete channel-spacing of 0.27 nm to 1.62 nm and corresponding time delay between two orthogonal polarization states of the beam of 30 ps to 5 ps, respectively, can be achieved. A spectral continuum is also achieved by introducing a time delay of 0.895 ps. On top of the experimental study, a mathematical model of channel-spacing tunable PMF-LSLF, which is used in the laser scheme, is also investigated using MATLABTM.