Film thickness, refractive index and dn/dT coefficient measurements of optical planar wave guides using prism coupler / Noorwati Md Saad

Optical planar wave guides have been fabricated on glass substrate using spin coater and characterized by SPA 4000 prism coupler using optical coupling technique at X=632.8 nm (laser 1) and X=1550nm (laser 2). Polymer material used was SU-8 2002 polymer. The advantage of using SU-8 polymer is the possibility to control and maintain its characteristic in high temperature. Film thickness of 0.5mm to >200 mm can be achieved with a single coat process. The prism coupling principle is used to determine the effective index, film thickness and coefficient of thermo optical. The refractive indices of the samples were 1.5934 and 1.5733 with the effective film thickness 3.19 urn and 3.39 nm respectively for laser 1 and laser 2 give the highest order modes characteristic. Information from this change in refractive index as a function of temperature change (dn/dT) can be used to relate relatively the effect in the materials when given different temperature range between 30°C to 65°C as well. This dn/dT measurement study was failed because of the error in heater stage to function in prism coupler.