Agapiou G S, Verber C M
Appl Opt. 1992 Mar 20;31(9):1257-60. doi: 10.1364/AO.31.001257.
A method for measuring the mode-index ratio n of two regions of a planar waveguide with an accuracy of better than 2 in 10(5) is presented. Simple and reliable techniques were utilized to produce two contiguous waveguides, with different refractive indices, on a common substrate. The two waveguiding regions were fabricated both in LiNbO(3) and in BK-7 glass by using titanium indiffusion followed by a proton-exchange (TIPE) process and a two-step Ag(+)/Na(+) ion-exchange technique, respectively. The measured mode-index ratios obtained by our method agreed well with values obtained with the conventional prism-coupling technique.
本文提出了一种测量平面波导两个区域模式折射率比(n)的方法，其精度优于(10^5)分之二。利用简单可靠的技术在同一衬底上制作出两个折射率不同的相邻波导。分别采用钛扩散后质子交换（TIPE）工艺和两步银离子/钠离子交换技术，在铌酸锂和BK-7玻璃中制作了两个波导区域。我们的方法测得的模式折射率比与传统棱镜耦合技术测得的值吻合良好。
