Temperature micro-sensor based on the thermo-optic effect in silicon

A new interferometric temperature sensor in silicon technology, suitable for full integration with other standard opto- and micro-electronic devices, has been realised. The sensor consists of a planar Fabry-Perot cavity defined on a chip by highly anisotropic Reactive Ion Etching. Temperature variations are detected by monitoring the transmitted intensity of a probing monochromatic (? = 1.5 ?m) light beam launched into the cavity. A 1700 ?m long cavity is demonstrated to allow a temperature resolution of about 1 K. Predictions on the limit resolution attainable with this technology are also given.