Design, modeling and characterization of stable, high Q-factor curved Fabry-Pérot cavities

In this paper, we introduce a novel design for high performance silicon-based Fabry-Pérot cavities and their corresponding design model. According to the design model, the new design shows higher stability, lower insertion loss and higher quality factor Q. Our methodology was based, on one hand, on taking advantage of light reflection and refraction over curved surfaces with curvatures along 2 orthogonal directions, in order to confine the Gaussian beam inside the cavity, thus reducing loss due to beam divergence. Such design enables approaching new limits, where Q-factor is mainly governed by the mirrors reflectance. On the other hand, the use of Bragg reflectors, obtained by DRIE etching enables reaching reflectances above 99%, thus enabling very high Q-factors.