啁啾相移光纤光栅的反射谱特性

相移光纤光栅作为透射型滤波器件降低了使用成本,在光通信和传感领域有着较高的应用价值.将传输矩阵法与谐振理论相结合,详细分析了相移量、相移点位置对啁啾相移光栅反射谱特性的影响,数值模拟和实验结果表明,啁啾相移光栅与均匀相移光栅不同,当位于啁啾光栅中点的相移调制量偏离π/2时,透射峰在偏离光栅反射谱中心的同时深度逐渐减小;当相移点在光栅上的位置发生变化时,透射峰位置也随之改变,但深度基本保持不变.利用啁啾光栅的这种特性,可形成具有多个透射峰的多点相移光栅.

Analysis for the Reflective Spectrum Characteristics of Chirped Phase-Shifted Fiber Gratings

As a transmission type filter, chirped phase-shifted fiber grating has the advantage of low cost, which makes it a critical component in optical communication and sensor system. Reflective spectrum of chirped phase-shifted fiber grating is analyzed about the influence of phase shift and position on reflection characteristic by the transfer matrix method combined with resonance theory. Different characteristics from uniform phase-shifted fiber gratings are obtained: the transmission window is away from the center of the reflective spectrum and becomes shallow when the phase shift in the center of the grating is unequal to π/2; the transmission window varies with the location of the π/2-phase shift, but all the transmission windows are of the same depth. Numerical predictions agree well with the experimental results. Multiple phase shifts can be used to open several transmission windows with the same depth which makes chirped phase-shifted gratings have a good application prospect in multi-channel filter and dispersion compensator.