Recent interest in optical sensors, especially optical biosensors, has led to the introduction of commercially available instrumentation and sensor schemes for label free, real time monitoring of intermolecular interactions. One of the promising optical structure is the grating coupler planar waveguide sensor, where high precision surface relief grating is used and a low cost manufacturing is needed. A practical method to mass-produce gratings with limited lateral dimension is to emboss master grating into a sol-gel waveguide film. With proper optimization of the sol-gel process, a wide time window is available to perform embossing and highly reproducible, cost effective grating structures can be replicated. In our practice SiO₂, TiO₂, SiO₂/TiO₂, Ta₂O₅ and a mixture of these sol-gel thin films are proved to be good candidates for low optical loss waveguide materials in which grating with 2400 line/mm periodicity could be directly embossed. The relatively wide time window for optimal embossing opens the possibility to develop grating structures with more than one grating. Producing multiple gratings separated laterally and/or vertically from each other is demonstrated.

Date Published: 15 May 2001
PDF: 8 pages
Proc. SPIE 4284, Functional Integration of Opto-Electro-Mechanical Devices and Systems, (15 May 2001); doi: 10.1117/12.426859

Published in SPIE Proceedings Vol. 4284:
Functional Integration of Opto-Electro-Mechanical Devices and Systems
Michael R. Descour; Juha T. Rantala, Editor(s)