Performance of Fabry–Perot microcavity structures with corrugated diaphragms

Abstract

A Fabry–Perot microcavity structure with a corrugated diaphragm as a deflecting diaphragm has been fabricated successfully. The composite dielectric layers of movable top and stationary bottom diaphragm of Fabry–Perot microcavity are optimized to have proper mechanical stability and optical response. Deflection behavior and device characteristics of a corrugated diaphragm case are compared with those of a planar diaphragm case. Output signal degradation as a function of pressure, “signal averaging effect”, is reduced using corrugated top diaphragm structures over planar top diaphragm structures. This is achieved by improving the flatness of the deflecting diaphragm in the optically sampled area of the microcavity structures. However, the corrugated structure shows a static deflection of the diaphragm without applying pressure due to the localized internal stress generated by the asymmetry of the corrugation on the diaphragm, “zero-pressure offset effect”. The existence and the influence of these parasitic effects have been observed by both real-time measurement and analytical simulation of the diaphragm.