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Active Core Optical Fiber Chemical Sensors and Applications
| Content Provider | Scilit |
|---|---|
| Author | Yallup, Kevin Iniewski, Krzysztof |
| Copyright Year | 2017 |
| Description | Book Name: Technologies for Smart Sensors and Sensor Fusion |
| Abstract | An optical fiber chemical sensor (OFCS) detects the existence of and measures the concentration of a compound in a sample through detecting the interaction of the compound with light propagating inside an optical fiber.$ ^{1} ^{,} ^{2}$ Depending on the location at which the interaction occurs, OFCS can be divided into two classes: active core OFCS (AC-OFCS)$ ^{3} ^{,} ^{4}$ and evanescent wave OFCS (EW-OFCS).$ ^{5} ^{–} ^{7}$ The principle of AC-OFCS and EW-OFCS, which detect the analyte’s optical absorption as sensing signals, are diagrammatically shown in Figure 7.1. In an AC-OFCS, the interaction of an analyte compound with the light occurs inside an optical fiber core, while in an EW-OFCS, the interaction of an analyte compound with the light occurs in the cladding layer of an optical fiber. A light beam traveling down an optical fiber can be scattered or absorbed by a compound existing inside the fiber core or inside the cladding. The light propagating in an optical fiber can also excite a compound in the fiber to a higher energy level and causes the emission of fluorescence (FL). All these interactions can be used in designing OFCS. Therefore, analytical spectroscopic techniques, such as ultraviolet/visible (UV/Vis) absorption spectrometry, near-infrared (NIR) and mid-infrared (IR) absorption spectrometry, Raman scattering spectrometry, FL spectrometry, have been used in OFCS design.$ ^{1} ^{–} ^{11}$ In addition, the existence of an analyte compound in the fiber core or cladding can change the refractive index of the core or cladding materials, which causes the change of light intensity guided through the fiber. This phenomenon has also been used in designing OFCS.$ ^{12} ^{–} ^{14}$ The characteristics, including sensitivity, precision, reversibility, response time, and selectivity, of an OFCS are decided by the properties of the compound to be detected, the chemical reactions involved in the sensing process, the analyte/light interaction used for the detection, the location of analyte/light interaction occurs, and the microstructure of the optical fiber core and the cladding. Figure 7.1 Diagrammatic graphs show the principles of AC-OFCS and EW-OFCS. The horizontal-lined parts in the fibers are where an analyte (or reaction product(s) of an analyte with a sensing reagent) interacts with light in the optical fiber. The vertical-lined parts in the fibers are not involved in the sensing, but only for light-guiding. Optical absorption spectrometry is used as an example in the graphs. I0 is the light intensity injected to the fiber, and I is the intensity of light transmitted out of the fiber. In AC-OFCS, most of the light are absorbed, while in EW-OFCS only small part of the light is absorbed. |
| Related Links | https://content.taylorfrancis.com/books/download?dac=C2013-0-16299-8&isbn=9781315215587&doi=10.1201/b16746-7&format=pdf |
| Ending Page | 124 |
| Page Count | 14 |
| Starting Page | 111 |
| DOI | 10.1201/b16746-7 |
| Language | English |
| Publisher | Informa UK Limited |
| Publisher Date | 2017-12-19 |
| Access Restriction | Open |
| Subject Keyword | Book Name: Technologies for Smart Sensors and Sensor Fusion Quantum Science and Technology Telecommunications Compound Optical Absorption Optical Fiber Core |
| Content Type | Text |
| Resource Type | Chapter |
