Three-Dimensional Fabry–Pérot Cavities Sculpted on Fiber Tips Using a Multiphoton Polymerization Process

Authored by: Jonathan W. Smith , Jeremiah C. Williams , Joseph S. Suelzer , Nicholas G. Usechak , Hengky Chandrahalim

Handbook of Scholarly Publications from the Air Force Institute of Technology (AFIT), Volume 1, 2000–2020

Print publication date:  December  2022
Online publication date:  December  2022

Print ISBN: 9781032116679
eBook ISBN: 9781003220978
Adobe ISBN:


 Download Chapter



This paper presents 3D Fabry–Pérot (FP) cavities fabricated directly onto cleaved ends of low-loss optical fibers by a two-photon polymerization (2PP) process. This fabrication technique is quick, simple, and inexpensive compared to planar microfabrication processes, which enables rapid prototyping and the ability to adapt to new requirements. These devices also utilize true 3D design freedom, facilitating the realization of microscale optical elements with challenging geometries. Three different device types were fabricated and evaluated: an unreleased single-cavity device, a released dual-cavity device, and a released hemispherical mirror dual-cavity device. Each iteration improved the quality of the FP cavity’s reflection spectrum. The unreleased device demonstrated an extinction ratio of around 1.90, the released device achieved 61, and the hemispherical device achieved 253, providing a strong signal to observe changes in the free spectral range of the device’s reflection response. The reflectance of the photopolymer was also estimated to be between 0.2 and 0.3 over the spectrum of interest. The dual-cavity devices include both an open cavity, which can interact with an interstitial medium, and a second solid cavity, which provides a static reference reflection. The hemispherical dual-cavity device further improves the quality of the reflection signal with a more consistent resonance and reduced sensitivity to misalignment. These advanced features, which are very challenging to realize with traditional planar microfabrication techniques, are fabricated in a single patterning step. The usability of these FP cavities as thermal radiation sensors with excellent linear response and sensitivity over a broad range of temperatures is reported. The 3D structuring capability of the 2PP process has enabled the creation of a suspended FP heat sensor that exhibited linear response over the temperature range of 20°C –120°C; temperature sensitivity of ~50 pm/°C at around 1,550 nm wavelength; and sensitivity improvement of better than 9× of the solidly-mounted sensors.

Search for more...
Back to top

Use of cookies on this website

We are using cookies to provide statistics that help us give you the best experience of our site. You can find out more in our Privacy Policy. By continuing to use the site you are agreeing to our use of cookies.