Optical fiber humidity sensor with ultrahigh sensitivity and based on all-agar F-P cavity

A humidity sensor and sensitivity technology, applied in the field of optical fiber humidity sensors, can solve the problems of information loss and weakening, and achieve the effects of short response time, reduced manufacturing cost, and easy packaging

Active Publication Date: 2017-01-04
HARBIN INST OF TECH SHENZHEN GRADUATE SCHOOL
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  • Abstract
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Problems solved by technology

Due to the secondary conduction of information, some information is lost or weakened

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  • Optical fiber humidity sensor with ultrahigh sensitivity and based on all-agar F-P cavity
  • Optical fiber humidity sensor with ultrahigh sensitivity and based on all-agar F-P cavity
  • Optical fiber humidity sensor with ultrahigh sensitivity and based on all-agar F-P cavity

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Embodiment Construction

[0018] specific implementation plan

[0019] The present invention will be further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0020] as attached figure 1 As shown, the ultra-high sensitivity optical fiber humidity sensor 100 based on the full agar F-P cavity of the present invention is composed of a single-mode optical fiber 101 and an agar F-P cavity 102. Due to the difference in refractive index, the optical fiber-agar and agar-air can be viewed as As two optical interfaces, this constitutes an F-P cavity. According to the working principle of the F-P cavity, the reflection spectrum can be modified by the refractive index (n) and the cavity length (L), which both change with the relative humidity (RH). The sensitivity of the sensor can be expressed as:

[0021] Δ λ Δ R H = λ ( 1 ...

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Abstract

The invention provides an optical fiber humidity sensor with ultrahigh sensitivity and based on an all-agar F-P cavity and a manufacturing method of the optical fiber humidity sensor. The sensor comprises a leading-in optical fiber and the humidity-sensitive agar F-P cavity composed of an agar colloid. The leading-in optical fiber and the agar F-P cavity are directly connected through an end face dipping method, the leading-in optical fiber is used for leading in a light source signal and transmitting reflected light, and the agar F-P cavity is used for sensing humidity changes in the environment. The agar colloid has hygroscopicity because the surface of the agar colloid contains a large number of hydrophilic groups, the agar colloid can expand when absorbing water and shrink when losing water, and the refractive index and size change at the same time. Changes of the refractive index and thickness of an agar film are fully utilized for manufacturing the sensor, the ultra-short agar F-P cavity can be used as a sensing unit, and therefore ultrahigh sensitivity is obtained. Besides, agar powder is cheap, easy to obtain and easy to dissolve in hot water, the cooled colloid is stable in optical property, the coating process is quite simple, a complicated operation process and expensive equipment are not needed, and the manufacturing cost of the sensor can be lowered.

Description

technical field [0001] The invention relates to the technical field of optical fiber sensing, in particular to an ultrahigh-sensitivity optical fiber humidity sensor. Background technique [0002] Humidity sensors are widely used in air-conditioning, food processing, chemical processing and building safety monitoring. Optical fiber humidity sensors have a series of advantages such as small size and light weight, and are more and more popular in the market. In order to detect changes in environmental humidity, there are basically two principles when making an optical fiber humidity sensor. One is based on the change of the refractive index, as described in Patent Document 1 (Chinese Patent Publication No. CN 101776493A), using a fence to surround the sensing sensitive liquid around the periphery of the optical fiber, the length of the sensing area is 0.1-6cm, and the operation is relatively complicated; The other is based on the volume change, as described in Patent Document...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/25G01N21/45
Inventor 田佳峻胡玲卢泽锦姚勇
Owner HARBIN INST OF TECH SHENZHEN GRADUATE SCHOOL
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