Design and Implementation of a Novel Measuring Scheme for Fiber Interferometer Based Sensors

Abstract

This paper presents a novel measuring scheme for fiber interferometer (FI) based sensors. With the advantages of being small sizes, having high sensitivity, a simple structure, good durability, being easy to integrate fiber optic communication and having immunity to electromagnetic interference (EMI), FI based sensing devices are suitable for monitoring remote system states or variations in physical parameters. However, the sensing mechanism for the interference spectrum shift of FI based sensors requires expensive equipment, such as a broadband light source (BLS) and an optical spectrum analyzer (OSA). This has strongly handicapped their wide application in practice. To solve this problem, we have, for the first time, proposed a smart measuring scheme, in which a commercial laser diode (LD) and a photodetector (PD) are used to detect the equivalent changes of optical power corresponding to the variation in measuring parameters, and a signal processing system is used to analyze the optical power changes and to determine the spectrum shifts. To demonstrate the proposed scheme, a sensing device on polymer microcavity fiber Fizeau interferometer (PMCFFI) is taken as an example for constructing a measuring system capable of long-distance monitoring of the temperature and relative humidity. In this paper, theoretical analysis and fundamental tests have been carried out. Typical results are presented to verify the feasibility and effectiveness of the proposed measuring scheme, smartly converting the interference spectrum shifts of an FI sensing device into the corresponding variations of voltage signals. With many attractive features, e.g., simplicity, low cost, and reliable remote-monitoring, the proposed scheme is very suitable for practical applications.

Special Issue “Fiber Optic Sensors and Applications”: An Overview

“…In "Design and Implementation of a Novel Measuring Scheme for Fiber Interferometer Based Sensors" [8], a measuring scheme for fiber interferometer based sensors was proposed to detect the equivalent changes of optical power corresponding to the variation in measuring parameters, and a signal processing system was used to analyze the optical power changes and to determine the spectrum shifts. A sensing device on polymer microcavity fiber interferometer was taken as an example for constructing a measuring system capable of long-distance monitoring of the temperature and relative humidity.…”

Tailoring Refractive Index and Adlayer Sensitivity of an Optical Fiber Fabry-Perot Interferometer by a Thin Layer Deposition

“…This type of sensors is widely considered for monitoring changes in optical properties or length in one of the optical Tailoring Refractive Index and Adlayer Sensitivity of an Optical Fiber Fabry-Perot Interferometer by a Thin Layer Deposition Dariusz Burnat, Norbert Kwietniewski, Krzysztof Bartnik, Marcin Koba, Olga Kochanowska, Kinga Kondracka, and Mateusz Śmietana O paths before the guided waves interfere [8]. On top of refractometric analysis, where n modifies the optical path and is measured [9], the interferometers can be also applied for label-free biosensing, facilitating identification of changes in density and/or thickness of the biological material bound of the surface of a sensor [10]. While many optical fiber interferometric sensors requires rather advanced, multistep fabrication processes, i.e., laser micromachining, chemical etching or splicing different types of fibers, and show no or little batch manufacturing capabilities, a Fabry-Perot interferometric (FPI) sensor, where all fabrication process is based on deposition of thin layers on optical fiber end-face, can be considered as an attractive alternative [11].…”