PMMA脊形光波导的设计与场分析

利用有效折射率法（EIM）理论设计了有机聚合物脊形光波导结构,并分析光波导中传输的模式场,确定出光波导结构的适宜尺寸范围。光波导结构中分别选用PMMA（聚甲基丙烯酸甲酯）与PDMS（聚二甲基硅氧烷）作为波导层与包层的材料,用光漂白法来实现脊形波导结构。首先利用EIM法分析脊形波导区的宽度与高度之间的关系对归一化色散曲线的影响,以及波导层与包层的折射率匹配的影响,然后又通过分析波导区传输的基模场来讨论传输的损耗问题。研究发现波导结构的脊宽与脊高之比w／d越大,其有效折射率neff越大,而此结构尺寸又需约束在一定范围内,否则将造成很大的传输损耗。

Design and Field Analysis of PMMA Rib Optical Waveguides

The structure of the polymer rib optical waveguide is designed by using effective index method(EIM),and the mode field distribution in these waveguides is analyzed to determine the suitable structural size range.For this rib waveguide realized by photo-induced bleaching,two kinds of polymer materials,PMMA and PDMS,are chosen as the core layer and the cladding layer respectively.Firstly with EIM,the influence of the relationship between the rib width w and height d on the normalized dispersion curve and the effect of refractive index matching are studied.Then,the base mode field in the waveguide is analyzed to discuss the transmission loss.It has been found that the larger the size ratio w/d of the PMMA rib waveguide is,the greater its effective index n_(eff)becomes.But this structure size should be limited in certain range,otherwise very large transmission loss would result.