Finesse of Stable Extrinsic Fiber Fabry-Pérot Cavities With Spherical Surfaces

Jiwon Choi,Kyoungsik Yu,Yeonghoon Jin,Gyeongho Son

doi:10.1109/jphot.2020.3027286

Jiwon Choi, Kyoungsik Yu + Show 2 more

Open Access

https://doi.org/10.1109/jphot.2020.3027286

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Abstract

In this work, we present a model for spectral transmittance of extrinsic fiber Fabry-Perot cavities using paraxial Gaussian approximation and ray transfer matrices. The finesse is obtained through a Lorentzian fitting of the spectral transmittance derived from the proposed model. The relationship between the finesse and the radius of curvature on both sides of the cavity was analyzed to obtain high finesse. The predictions of the model are found to be in good agreement with the experimental results for the fabricated cavities.

Highlights

Optical Fabry-Pérot cavities (FPCs) have played important roles in optical communication [1], [2], optical sensors [3]–[5], and quantum electrodynamics [6], [7]
To experimentally verify the validity of our model, four different types of single-mode fiber (SMF)-28-based Fiber-based FPCs (FFPCs) with a combination of flat/curved and uncoated/coated facets were fabricated by chemical wet etching [21] and a subsequent metal deposition process [22]
A framework was presented by which to obtain the finesse of extrinsic FFPC

Summary

Introduction

Optical Fabry-Pérot cavities (FPCs) have played important roles in optical communication [1], [2], optical sensors [3]–[5], and quantum electrodynamics [6], [7]. Finesse is defined by the effective average number of round-trips of the light before it leaves the cavity, and this is limited by the cavity mirror reflectivity for extrinsic FFPCs. In practice, the finesse values are usually affected by a number of non-idealities, such as the misalignment of the mirrors and inappropriate mirror curvatures. While the guided mode radius for the output fiber is fixed, the effective beam size varies inside the FFPC, which inevitably results in non-ideal output coupling to the output fiber. On this account, in-depth theoretical modeling for the behavior of the beam propagation inside the extrinsic FFPC

Results

Discussion

Conclusion