An optically addressed sensing system

摘要

An optically addressed sensor system uses a Fabry-Perot interferometer 4 to sense a measurand such as pressure or temperature by way of a cavity formed by (inter alia) a recess in a micromachined diaphragm, setting an optical path difference greater than the coherence length of a broadband optical source 1. The output is recovered by way of a further interferometer 6 with a similar optical path difference. Thus, information is encoded in the wavelength domain avoiding errors due to attenuation, loss, source variation etc. Suitable substrate arrangements are disclosed for the cavity which are suitable for mass production.