Polymer Optical Fiber Temperature Sensor With Dual-Wavelength Compensation of Power Fluctuations

Abstract

Abstract:The design and development of a plastic optical fiber macrobend temperature sensor is presented. The sensor can op-erate in a temperature range from −55 to 70 °C and has a linear response versus temperature with a sensitivity of 8.95·10−4 °C−1. The sensor system uses the ratio of transmittance at two wave-lengths to implement a selfreferencing technique in order to avoid undesirable power fluctuations influence. The transmittance ratio precision is 0.1%. An analysis has been developed to find the two wavelengths which ratio offers the highest linearity and sensitiv-ity response. Experimental results are successfully compared with theoretical approaches.

PDMAA Hydrogel Coated U-Bend Humidity Sensor Suited for Mass-Production

“…Since non-functionalized step-index multi-mode fibers were utilized as intrinsic temperature sensors in a couple of works [15,19], a combined sensitivity of our sensor towards relative humidity and temperature is possible. In both works, a U-bend is applied to the fiber to lower the local numerical aperture and thereby increase the sensitivity towards temperature changes.…”

“…In one work, the different prefixes of the thermo-optical coefficients of a silica glass fiber and its silicone rubber cladding is utilized for temperature detection [19]. With the smaller differences between the thermo-optical coefficients of the core and the fluorinated cladding of standard-POF, temperature detection is also possible [15]. However, in the second case, a rather small radius of the U-bend of around $1 \mathrm{mm}$ is necessary, and the readout is done by comparing the intensity variations of two different transmitted wavelengths which are utilized to increase sensitivity.…”

“…Since a comprehensive investigation of the geometrical characteristics is given in [7,15], we will restrict our description here to a brief summary. Depending on the entrance height $h$ and the beam angle $\theta$ that the individual beam exhibits upon entrance to the bent region with respect to the surface normal, the new TIR angle is $\varphi ={\sin }^{-1}\left(\frac{R+h}{R+2\rho }\sin \theta \right)$ in the case of the outer boundary and $\delta ={\sin }^{-1}\left(\frac{R+h}{R}\sin \theta \right)$ in the case of TIR on the inner boundary.…”

Efficient Multiplexer/Demultiplexer for Visible WDM Transmission over SI-POF Technology

“…Apart from visible WDM SI-POF links, these low insertion losses Mux/DeMux can also be used in intensity based fiberoptic sensing configurations using WDM as the self-referencing principle [27].…”

High sensitivity micro-fiber Mach-Zehnder interferometric temperature sensors with a high index ring layer

“…In general, with the presence of the HIRL, it is advantageous to increase the OPD and its sensitivity or to convert the fiber core mode into the 'bottle beam' modes in microfiber interferometers. With the use of the HIRL, the temperature sensitivity can be improved and data shows that it is ∼ 11.7 times higher, at 186.6 pm/°C (for the silica fiber MZI), than has been seen from other, previous reports in the literature [1,[11][12][13][14][15][16][17][18][19][20][21][22]].…”