Miniature pH optical fiber sensor based on waist-enlarged bitaper and mode excitation
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- 作者：Wei Chang Wong ; Chi Chiu Chan ; Pengbing Hu ; Jin Rong Chan ; Yi Ting Low ; Xingyong Dong ; Kam Chew Leong
- 关键词：Optical fiber sensor ; Waist enlarged bitaper ; Polyvinyl alcohol ; Poly acrylic acid ; Cladding mode excitation ; pH sensor
- 刊名：Sensors and Actuators B: Chemical
- 出版年：February, 2014
- 年：2014
- 卷：191
- 期：Complete
- 页码：579-585
- 全文大小：1709 K
文摘
A polyvinyl alcohol/poly-acrylic acid (PVA/PAA) hydrogel coated optical fiber interferometer was been evaluated as a pH sensor. The interferometer, which comprises a waist-enlarged bitaper, a round tip and a tantalum pentoxide layer displays high refractive index (RI) sensitivity. With the hydrogel coated, the sensor's optical interference fringes shifted with exposure to varying pH solutions. High pH sensitivity of 1.58 nm/pH was achieved for pH 2.48-6.47. The miniature sensor demonstrates little hysteresis, high repeatability and low cross-sensitivity to temperature. A rising/falling time of 10/11 s for the sensor time response was acquired, respectively.