Quick-response conical micro-nano optical fiber humidity sensor and preparation method thereof

Abstract

The invention discloses a quick-response conical micro-nano optical fiber humidity sensor and a preparation method thereof. The humidity sensor comprises a broadband light source, a conical micro-nano optical fiber structure and an optical spectrum analyzer which are sequentially connected, wherein the conical micro-nano optical fiber structure comprises a conical waist region and two conical transitional regions which are positioned at two ends of the conical waist region; the two conical transitional regions are connected with the broadband light source and the optical spectrum analyzer through a standard optical fiber respectively. The method comprises the following steps of: (1) removing a coating layer of a double-clad optical fiber to remain a bare optical fiber containing a fiber core, an inner cladding layer and an outer cladding layer; (2) fusing two ends of the bare optical fiber with the standard optical fiber through an optical fiber welding machine respectively; (3) performing fused biconical taper on the bare optical fiber to obtain the conical micro-nano optical fiber structure; (4) connecting the standard optical fiber of which the two ends are fused with the broadband light source and the optical spectrum analyzer to form the conical micro-nano optical fiber humidity sensor. The quick-response conical micro-nano optical fiber humidity sensor has a simple optical fiber structure, and is high in response speed, wide in measurement range and high in detection sensitivity.

Description

technical field [0001] The invention relates to an optical fiber humidity sensor and a preparation method thereof, in particular to a fast-response tapered micro-nano optical fiber humidity sensor and a preparation method thereof, belonging to the field of environmental humidity measurement. Background technique [0002] With the development of modern optical fiber sensing industry, the research on all-fiber devices has been paid more and more attention by scientific researchers and people in the optoelectronic industry. The improvement of the requirements of integration and energy consumption has made the characteristic line width or diameter of the current all-fiber devices reach the sub-wavelength and nanometer scale. Micro-nano fiber is an optical fiber with a diameter of micron or nanometer. It has the unique optical characteristics of strong optical field confinement and strong evanescent field transmission. Using this strong evanescent field coupling can realize effic...

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Problems solved by technology

However, the sensing sensitivity and response time of these methods are still greatly limited, for example, the literature "Teck L.Yeo, Tong Sun, Kenneth T.V.Grattan, David Parry, Rob Lade, and Brian D.Powell, Polymer-coated fiber Bragg Grating for relative humidity sensing, Sensors Journal, IEEE, 2005, 5(5): 1082-1089." It is proposed to coat the surface of fiber Bragg grating with a polymer film to increase the sensitivity to humidity. This method has a complicated manufacturing process. The sensitivity obtained experimentally is 4.5pm / %RH (unit humidity), "Francisco J.Arregui, Yanjing Liu, Ignacio R.Matias, Richard O.Claus, Optical fiber humidity sensor using a nano Fabry-Perot cavity formed by the ionic self-assembly method, Sensors and Actuators B: Chemical, 1999, 59(1): 54-59." proposed to use the fiber optic Fabry-Perot cavity as a fast-response humidity sensor, and the obtained response time is 1s, which cannot meet the ultra-fast response request

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