Fertein E, Przygodzki C, Delbarre H, Hidayat A, Douay M, Niay P
Appl Opt. 2001 Jul 20;40(21):3506-8. doi: 10.1364/ao.40.003506.
We report on permanent refractive-index changes as great as 6 x 10(-3) in standard fibers on irradiation with tightly focused femtosecond (120-fs) near-IR (lambda = 800-nm) pulses. The refractive-index increase was measured through changes in the transmission spectrum of an UV photowritten Bragg-grating-based Fabry-Perot interferometer. We depict the dependence of the index variation on exposure time. The changes in refractive index can be optimized after a few seconds of irradiation. The measured induced excess loss increases during near-IR exposure.
我们报道了在标准光纤中，用紧聚焦飞秒（120飞秒）近红外（λ = 800纳米）脉冲照射时，永久折射率变化高达6×10⁻³ 。通过基于紫外光写入布拉格光栅的法布里-珀罗干涉仪的透射光谱变化来测量折射率的增加。我们描绘了折射率变化对曝光时间的依赖性。在照射几秒钟后，折射率的变化可以得到优化。在近红外曝光期间，测得的诱导额外损耗会增加。
