论文部分内容阅读
本文介绍了对矩形保偏光纤偏振性能的实验性研究。测量了20、40、100、310和804m长光纤在1320nm波长的消光比。证明长度和矩形保偏光纤消光比之间的关系与随机耦合理论推导出的模型非常一致,这是由于在卷绕和包封矩形保偏光纤时非常细心,致使引入的外部扰动最小之故。光纤的矩形结构也使卷绕和包封变得更为方便。测得偏振保持参数为2.08±0.09×10~(-6)m~(-1)。测定了各种长度光纤的偏振态与线性偏振埸入射角的函数关系。当光纤长度≥100m时,消偏振效应消除了除线性轴偏振态外所有其它的偏振态。当光纤长度较短时,其它偏振态会在光纤中传播。然而如果场的入射角在光纤偏振轴的5°之内,那末只有线性轴偏振态会在光纤中传播。采用弹光点扰动技术,在1320nm波长直接测得拍长为6.78±0.36nm,从而得知折射率引起的相位差为1.95×10~(-4)。
This paper presents an experimental study on the polarization performance of rectangular PM fibers. The extinction ratio of the 20, 40, 100, 310 and 804 m long fibers at 1320 nm was measured. The relationship between length and the extinction ratio of a rectangular PM fiber is shown to be in good agreement with the model derived from stochastic coupling theory due to the extra care taken when wrapping and encapsulating the PM fiber so that the external disturbance introduced is minimized. The rectangular structure of the fiber also makes winding and wrapping even easier. The measured polarization retention parameter was 2.08 ± 0.09 × 10 ~ (-6) m ~ (-1). The polarization dependence of various lengths of fiber as a function of incident angle of linearly polarized light is measured. When the optical fiber length ≥ 100m, the depolarization effect eliminates all the polarization state except the linear axis polarization state. When the fiber length is shorter, other polarization states propagate in the fiber. However, if the incident angle of the field is within 5 ° of the fiber’s polarization axis, then only the linear axis polarization will propagate in the fiber. Using the spot-light perturbation technique, the beat length measured directly at 1320 nm was 6.78 ± 0.36 nm, and the phase difference caused by the refractive index was 1.95 × 10 -4.