Analysis of micromachined Fabry-Pérot cavities using phase-sensitive optical low coherence interferometry: Insight on dimensional measurements of dielectric layers

Herein, we highlight a behavior underlying the physics of Fabry-Pérot micro-cavities with distributed reflectors as there is a need to discriminate between effective and physical cavity lengths. Hence, Phase-Sensitive Optical Low Coherence Interferometry has been implemented to characterize micro-cavities with planar or curved reflectors. Beside the retrieved physical length, we obtain valuable information about the reflector thickness and number of layers. The accuracy of the technique has been estimated. Results suggest that this technique might be suitable to retrieve dimensional characteristics of any device constructed from multiple dielectric layers, whose thickness ranges from 2 micrometers up to hundreds of micrometers.