低偏振相关损耗全息光栅波分复用器的设计

对基于掺杂铌酸锂材料的体光栅波分复用器主要结构和光栅记录参量提出了一种优化设计方法.采用严格耦合波理论,对两种偏振不同入射角和不同记录晶体厚度下的器件关键性能参量,如插入损耗和偏振相关损耗等进行了优化.数值结果证明采用优化设计的晶体厚度和光栅记录时的入射角,在获得相当低的偏振相关损耗的同时,也能够获得较低的插入损耗,实现了综合性能优化的波分复用器设计.实验结果证明用优化设计的参量能有效降低波分复用器件的插入损耗和偏振相关损耗.

Design of Wavelength Division Demultiplexers Based on Holographic Gratings with a Low Polarization Dependent Loss

An optimizing method of main structure parameters(e.g.,the thickness of the crystal) and writing conditions(e.g.,the incident angle) is presented for a holographic grating wavelength division demultiplexer based on photorefractive LiNbO_3 crystals.The key performance parameters of the demultiplexer,such as the loss and the polarization dependent loss(PDL),are optimized by selecting favourite structure parameters using a rigorous coupled wave analysis method.Numerical results show that a low loss and a low PDL can be achieved by using the optimal crystal thickness and incident angle.The designed demultiplexer obtains the favourite synthetical performance for an actual application.The experimental method of the grating recorded is also introduced in the present paper.The experimental results accorded with theoretical computation commendably by testing the three different specimens.