Design of Wavelength Division Demultiplexers Based on Holographic Gratings with a Low Polarization Dependent Loss
低偏振相关损耗全息光栅波分复用器的设计

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.