Investigation of single-polarized phosphate glass fiber laser and its self-pulsing behavior

A compact short-cavity fiber laser configured with Er³⁺/Yb³⁺ highly co-doped phosphate glass fiber which has linear polarization and single frequency output is fabricated experimentally. The threshold power of the laser is about 30m W, and larger than 100mW output power is achieved with slope efficiency of 20% at 1549nm. At the meantime, sine modulation, positive pulse and chaos state in the output power at different experimental condition are observed. And a new theoretical model is proposed to describe the mechanism of the observed intensity instability behavior in the fiber laser and the numerical results proved its feasibility. It is confirmed that the self-pulsing behavior is mainly caused by different small external feedback. So there is an efficient way to overcome self-pulsing behavior in the compact single polarized fiber laser by minimizing the external feedback.