Tunable multi-wavelength SOA fiber laser based on a Sagnac loop mirror using an elliptical core side-hole fiber

We propose and experimentally demonstrate a tunable multi-wavelength SOA fiber laser based on a Sagnac loop mirror using elliptical core side-hole fiber. We fabricated different types of elliptical core side-hole fiber with elliptical or circular cladding shape. The measured modal birefringence of the fabricated fiber was 1.7x10(-4) (elliptical shape) and 1.16x10(-4) (circular shape), respectively. By carefully adjusting the polarization controller inside the cavity, we could obtain 18 discrete channels with SNR over 30 dB and channel spacing of 0.8 nm and 10 discrete channels with SNR over 30 dB and channel spacing of ~1.4 nm. The proposed fiber laser was rather stable and the temporal power fluctuation was less than 0.8 dB. In addition, by thermally heating the elliptical core side-hole fiber in the Sagnac loop, we could obtain a tunable multi-wavelength fiber laser.