激光器光谱线宽对布里渊光纤谐振腔谐振特性的影响

针对激光器光谱线宽不可能严格为零的问题,在激光相干理论的基础上,采用光波场叠加的方法计算了布里渊光纤谐振腔的循环光强,详细分析了激光器光谱线宽对布里渊光纤谐振腔谐振谱线宽度和精细度的影响,并进一步分析了光谱线宽对谐振腔受激布里渊散射阈值的影响,最后,引入了线宽压缩的概念分析了布里渊光纤陀螺的灵敏度。分析表明,除了耦合器插入损耗外,激光器光谱线宽也是影响精细度的重要因素,具体影响程度与激光器光谱线宽及谐振腔本征谱线宽度间的相对大小有关,受激布里渊散射阈值随激光器线宽的增加而近似线性增加,另外在其他参数相同的情况下,布里渊光纤陀螺的灵敏度比谐振式光纤陀螺高大约三个数量级。本文为布里渊光纤陀螺的光源选择及光路参数的优化设计过程提供了理论依据。

Influence of spectral linewidth of laser on resonance characteristics of Brillouin fiber ring resonator

A simple optical field overlap method is applied to calculate the circulating light intensity in Brillouin fiber ring resonator based on laser coherence theory to solve the problem that laser linewidth can not strictly be zero.The analysis has been made on: 1)the influence of resonance characteristics by spectral linewidth;2) the relationship between spectral linewidth and threshold of simulated Brillouin scattering;3) the sensitivity of Brillouin fiber optic gyroscope(B-FOG) based on the concept of linewidth narrowing.The analysis shows that finesse of the resonator is significantly influenced by the coupler insertion loss and the linewidth of laser.Threshold of stimulated Brillouin scattering increases linearly with the increase of laser linewidth.The sensitivity of B-FOG is about three orders higher than that of R-FOG when with the same other parameters.This paper provides a theoretical basis for source selection and optical parameters’ optimization of the B-FOG design process.