All-POF coupling ratio-imbalanced Sagnac interferometer as a refractive index sensor

Abstract

A polymer optical Sagnac interferometer is proposed as a compact and low-cost refractive index sensor for the first time to our best knowledge. The Sagnac interferometer is fabricated by only one piece of fiber to facilitate its fabrication and to avoid losses due to misalignment or fusion. The coupler was developed based on chemical and twisting techniques of ∼ 5 c m of fiber. We modified the coupling ratio by varying the refractive index of media surrounding the coupler and consequently modified the transmission. For several values of mass percent concentration of sugar solutions surrounding the coupler, we found that transmittance decreases as the mass concentration increases. However, the decay is faster for the low concentration, while the decay is slower for higher concentrations. Two sets of experiments were carried out, at high ( ≥ 1 gm/100 ml) and low ( &lt;<!-- 1 g m / 100 m l ) mass concentration of sugar solutions. The calibration of the sensor was done at 733 nm, where the response of the interferometer displays larger transmission variations for different solutions. The refractive index estimation was possible by correlation of the transmittance function (calculated by fitting the experimental data) with a linear refractive index model. The estimated resolution of the system is 0.057 weight percent of sugar solution, determined by the noise of the system.

Plastic Optical Fiber Spectral Filter Based on In-Line Holes

“…The plastic optical fiber loop mirror (POFLM), shown in Figure 1b, comprises a drum with a 10 cm diameter, around which the 1.5 m POF is coiled. For the POFLM, the coupler manufacturing process follows the same procedure as described in [15]. However, in this study, additional environmental protection was provided to the coupler by enclosing it within a metallic tube.…”

“…Although optical fibers are generally composed of silica, POFs present the additional advantages of ease of fabrication and operation, a low cost, high flexibility, softness, a light weight, higher fracture toughness, higher strain limits, and biocompatibility when compared to silica optical fibers [3,4]. Such properties make POFs a relevant technology for applications such as sensors [5][6][7]; local area networks [1,8]; and the fabrication of devices such as tapers [9], connectors [10], couplers [11,12], gratings [13,14], and even interferometric systems [5,15].…”

Low-Cost Fiber-Optic Sensing System with Smartphone Interrogation for Pulse Wave Monitoring

“…A 1 × 2 Y-coupler was fabricated with a cutting and gluing technique as shown in Figure 2. Among the many methods of manufacturing such splitters [50][51][52][53][54][55][56][57], this was chosen as one of the simplest and less time-consuming. The first PMMA fiber was cut at an angle of 90 degrees and two others were cut at an angle of 14 degrees.…”

Temperature Sensors based on Polymer Fiber Optic Interferometer

“…This allows for a significant reduction in costs [113] of implementation and subsequent measurement system operation. Sensors that allow temperature measurement of chemical and biochemical processes are required in both industrial production and laboratory research.…”