Optical Fiber Fabry–Perot Humidity Sensor Filled with Polyvinyl Alcohol

Abstract

An optical fiber Fabry-Perot (F-P) humidity sensor was fabricated using polyvinyl alcohol (PVA) and a single-mode optical fiber. Humidity response experiments were carried out in the humidity range of 22-98% RH with a cycle of rising and falling humidity to investigate the repeatability of its response to humidity. The sensitivity was 36.71 pm/% relative humidity (RH) with linearity of 0.99773 under rising humidity and 37.63 pm/% RH with linearity of 0.99846 under falling humidity. The experimental results showed that the humidity sensor has good repeatability and consistency. Typical tests under 75% RH were performed to obtain the dynamic response characteristics. The dynamic response wavelength drift was measured repeatedly, which showed a high response speed. The response time and recovery time were 1.5 and 2.5 s, respectively. Furthermore, the dependence of the response characteristics on the cavity length and PVA concentration was investigated. The experimental results showed that the sensor maintains a highly linear response to humidity over a wide range of RH regardless of the cavity length and PVA concentration. The research results indicate the possibility of realizing an easily fabricated, low-cost, and high-performance optical fiber humidity sensor.

Compact fiber Fabry–Perot sensors filled with PNIPAM hydrogel for highly sensitive relative humidity measurement

“…In order to detect RH, fiber optic humidity sensors are fabricated, which can be roughly achieved by forming FPI on the fiber end face and coating the fiber surface with hydrophilic materials. These include swelling effects based on hydrophilic materials such as polyvinyl alcohol (PVA) [1] , poly (ethylene oxide) (PEO) [2] , Nafion® [3] , polymer microrods [4] and whole agar [5] . In the swelling effect, the dimension of the hydrophilous material will swell with the change of RH.…”

Demonstration of a ZnO-Nanowire-Based Nanograting Temperature Sensor

“…Their advantages of compact size, easy fabrication, low cost, compatibility to fiber system, and immunity to the electromagnetic environment are favored. Many fiber-based sensors have been made in past decades to sense physical and chemical parameters like temperature [1][2][3], refractive index [4,5], humidity [6][7][8], pressure [9,10], magnetic fields [11,12], bio/chemical compounds [13,14] or multi-parameters [15][16][17]. Standard silica fiber [18][19][20], photonic crystal fiber [21,22], and fibers with well-designed structures [23][24][25] based systems are widely invented.…”

Simultaneous Measurement of Humidity and Temperature Using a Hybrid Plasmonic Waveguide Bragg Grating

“…electronic RH sensors, fiber-optic sensors have received more attention owing to their compact size, convenient integration, cost-effectiveness, immunity to electromagnetic interference, and high resolution [5], [6], [7]. So far, various types of fiberoptic humidity sensors have been proposed [8], [9], [10], [11], [12]. Due to the sensitive characteristics towards RH and temperature, polyvinyl alcohol (PVA) has found extensive applications in the development of RH sensors based on wavelength demodulation.…”