环形腔光纤激光器边带偏振不稳定性

为研究双折射光纤的高功率环形腔光纤激光系统输出稳定性,提出了一种可能存在的矢量调制不稳定现象——边带偏振不稳定性(SPI)。结合偏振不稳定性与边带不稳定性的研究方法,建立了偏振光在线性双折射掺杂光纤的环形腔中传输时满足的非线性薛定谔方程,并求得了高双折射光纤中信号光偏振方向与主轴重合时扰动边带的解析解。研究结果表明,在正常色散情况下,沿主轴偏振的信号光在环形激光器中传输时,各阶扰动边带所获得的峰值增益随着信号光功率的变化而呈锯齿状分布,并随功率的增加而趋于一稳定值。

Sideband Polarization Instability in Fiber Ring Lasers

To investigate the output stability of a high power fiber ring laser system containing a birefrigent fiber, a kind of vector modulation instability — sideband polarization instability (SPI) was proposed. Nonlinear Schrdinger equations describing the polarized light propagating in a unidirectional fiber ring laser were deduced based on the methods of polarization instability and sideband instability. General coupling equations governing the evolution of sidebands caused by SPI in strongly birefringent fiber ring lasers were derived. Analytical solution was obtained for the case when the signal light was polarized along one principle axis of the fiber. The results show that in normal dispersion region, the sideband gain induced by perturbations to signal light propagating along the principle axis evolves in a saw-tooth manner, and approaches a fixed value with the increase of signal power.