Conception of optical integrated circuits on polymers

Abstract

The authors present a successful design, realisation and characterisation of single-mode TE 00–TM 00 rib optical waveguides composed of SU-8 polymer. For the simulation, a generic software package that provides an interactive and graphical environment for analysis by polarised Semi-Vectorial Finite Difference (SVFD) method of all kinds of integrated optical waveguides, such as buried channel, raised strip, rib, embedded, or ridge waveguides, has been implemented and tested. In this method we have taken into account the terms due to the interface between each layer. After realisation of various single mode optical waveguides on SU-8 polymer and Spin on Glass (SOG) like straight, S-bends, Y-junctions, Mach-Zehnder (MZ) interferometers, the linear absorption coefficient of energy α TE–TM of such rib waveguides have been measured and estimated, respectively, near 0.32 and 0.46 cm −1 for both optical modes TE 00 and TM 00 on Si/SiO 2/SU-8 structures. These values yield optical losses of 1.36 and 2.01 dB/cm. Optical losses ascribed to Si/SiO 2/SOG/SU-8 microstructures have been evaluated to 2.33 and 2.95 dB/cm for both polarisations. Hence, as a crucial step for designing polymer components devoted to microsensors applications (pressure, heat transfert), the SU-8 polymer appears as a promising candidate for integrated optics with low optical losses.