Abstract

Interferometry is a crucial investigative technique used across diverse fields to achieve high-precision measurements. It works by analyzing the phase difference between two interfering waves, which results from variations in optical path lengths within an interferometer. We introduce a novel method for directly measuring changes in the phase difference within an optical interferometer, importantly, with the added advantage of a controllable enhancement factor. This approach is achieved through a two-step process: first, the optical phase difference is encoded into a sub-GHz radiofrequency (RF) signal using microwave-photonic manipulation; then, RF interferometry-assisted phase amplification is implemented at the destructive interference point. In our experiments, we demonstrate a phase sensitivity of 2.14rad/nm operating at 140 MHz using a miniature in-fiber Fabry–Pérot interferometer for sub-nanometer displacement sensing, which reveals a sensitivity magnification factor of 258.6. With further refinement, we anticipate that even higher enhancement factors can be achieved, paving the way for the development of cost-effective, ultra-sensitive interferometry-based instruments for high-precision optical measurements.

Department(s)

Electrical and Computer Engineering

Publication Status

Open Access

Keywords and Phrases

fiber-optic interferometer; interferometry; microwave photonics; phase sensing; radiofrequency interferometry

International Standard Serial Number (ISSN)

2791-1519

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2026 The Authors; Society of Photo-Optical Instrumentation Engineers (SPIE), All rights reserved.

Publication Date

01 Jan 2026

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