Abstract

There is an increasing need for reliable, repeatable gas/aqueous phase chemical sensors in many industrial, medical and environmental applications. Much work at present is being done in the area of sol-gel sensing and more specifically planar waveguide based chemical sensors. This form of chemical sensor utilises evanescent wave sensing. One of the key issues in this configuration is the coupling mechanism into the waveguide. Many groups have reported the fabrication of sensor platforms, which contain low loss planar waveguides along with a variety of techniques. Prism coupling is a popular mechanism for launching light into a waveguide. However, bulky optics and precise beam alignment can lead to lack of repeatability. Another mechanism commonly used to launch light into a waveguide is grating coupling. Many different fabrication processes are used to produce grating couplers on the surface of waveguides. The technique used in this work was the embossing procedure.

© 1998 IEEE