Paper
11 April 2019 Multi-application miniature fiber optic interferometer
Author Affiliations +
Abstract
In this work, we present a concept and method to fabricate miniature, high-quality optical fiber interferometers for sensing applications. The sensitive part of our devices consists of an off-center polymer micro-cap bonded on the end of a single mode fiber (SMF). The SMF end can be cleaved with a small angle or polished flat. In our devices, the reflection from the interface between the polymer and the external medium can be adjusted with an axial misalignment between the core of the SMF and the polymer micro-cap. This allows us to control the fringe contrast of the interference pattern. We fabricated several samples and they were tested as temperature, refractive index, and humidity sensors. In each case, our sensors were compared with commercial ones. Our results suggest that our devices are as accurate and sensitive as wellcalibrated electronic sensors. The sensitivities were found to be 270 pm/°C for temperature sensing and 0.04 RH% for humidity sensing. As refractometers, our interferometers have a resolution of 10-4 over a broad measuring range that goes from 1 to 1.54. Some applications of the devices here proposed can be monitoring of temperature or humidity in small spaces and refractive index of liquids inside of micro-fluidic channels. An advantage of our sensors is their broad operating wavelength range (from 800 to 1600 nm, approximately). In addition, the thermo-optic or thermal-expansion coefficients of polymers can be tailored. This may allow, for example, to tailor the performance of our sensor depending on the parameter to be sensed.
© (2019) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Oskar Arrizabalaga, Joseba Zubia, Idurre Sáez de Ocáriz, and Joel Villatoro "Multi-application miniature fiber optic interferometer", Proc. SPIE 11028, Optical Sensors 2019, 110280C (11 April 2019); https://doi.org/10.1117/12.2522175
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KEYWORDS
Single mode fibers

Polymers

Sensors

Interferometers

Refractive index

Humidity

Calibration

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