用于FBG解调的阵列波导光栅设计与性能分析

Array Waveguide Gratings for FBG Demodulation Design and Performance Analysis

首先从理论上详细分析阵列波导光栅的串扰、插入损耗和带宽对解调系统的动态范围、波长分辨率及解调精度的影响。结果表明,带宽越大,解调系统的动态范围越大,但波长分辨率会有所下降;串扰越小,解调精度越高。然后从理论上研究影响阵列波导光栅输出光谱带宽的因素,如阵列波导光栅的衍射级数、阵列波导数及喇叭口宽度等。结果表明,当阵列波导数越小和锥形波导的开口宽度越大时,则阵列波导光栅的通带带宽越大。最后设计一款基于2%折射率差二氧化硅材料体系的阵列波导光栅,其具有带宽宽、损耗低和串扰低等特点,为基于阵列波导光栅的光纤光栅解调系统的研究提供理论指导,并指明器件及系统的优化方向。

We theoretically analyze influence of the crosstalk,insertion loss,and bandwidth of the arrayed waveguide grating on the dynamic range,wavelength resolution,and demodulation accuracy of the demodulation system.The results show that the larger the bandwidth,the larger is the dynamic range of the demodulation system;however,the wavelength resolution will decrease.It also shows that the smaller the crosstalk,the higher is the demodulation accuracy.Then,we theoretically investigate the factors affecting the output spectral bandwidth of the arrayed waveguide grating,such as the number of diffraction orders of the arrayed waveguide grating,the number of arrayed waveguides,and the width of the horn.The results show that the passband bandwidth of the arrayed waveguide grating is larger when the number of waveguides is smaller and the width of the tapered waveguide opening is larger.Finally,we design an arrayed waveguide grating based on a 2%refractive index difference silica material system,which has the characteristics of wide bandwidth,low loss,and low crosstalk.It provides theoretical guidance for research on fiber-grafting demodulation systems based on arrayed waveguide grating.We then specify the optimization direction of the device and system.