论文部分内容阅读
发现高频CO2激光脉冲写入的长周期光纤光栅(LPFG)具有独特的扭曲特性:1)扭曲特性具有明显的扭曲方向相关性———顺时针扭曲时谐振波长发生“红”移,逆时针扭曲时谐振波长发生“蓝”移,无论顺时针还是逆时针扭曲损耗峰幅值都近似线性减小;2)若被扭曲的光纤比被扭曲的长周期光纤光栅长得多,则扭曲时长周期光纤光栅谐振波长和幅值的变化出现周期性的起伏。利用扭曲光栅引起椭圆双折射进而导致偏振态变化的相关理论合理解释了这些独特的扭曲特性。
It has been found that the long-period fiber grating (LPFG) written by high-frequency CO2 laser pulses has unique twist characteristics: 1) Distortion characteristics have obvious twist direction correlation --- When the clockwise twist occurs, the resonance wavelength is “red” The “blue” shift of the resonant wavelength occurs when distorted, and the amplitude of the peak loss decreases approximately linearly both clockwise and counterclockwise. 2) If the distorted fiber is much longer than the distorted long-period fiber grating, Fiber grating resonant wavelength and amplitude changes appear cyclical fluctuations. The related theory of using twisted grating to induce elliptical birefringence, which in turn leads to the change of polarization states, explains these unique distortions reasonably.