Cladding supermode interference based fiber reflective probe sensor and manufacturing method thereof

Abstract

A cladding supermode interference based fiber reflective probe sensor is composed of a single-mode fiber and a cut all-solid photon band-gap fiber, the end, close to the single-mode fiber, of the all-solid photon band-gap fiber is etched with a long-period grating, and the tail end of the all-solid photon band-gap fiber includes a reflection surface. A manufacturing method of the sensor comprisesthat 1) the two ends of the all-solid photon band-gap fiber are connected with a broadband light source and a spectrometer via single-mode fibers respectively; 2) one end of each single-mode fiber atone side of the all-solid photon band-gap fiber is fixed, the other end of the single-mode fiber is loaded with a counterweight, and the all-solid photon band-gap fiber is placed in a processing areaof a carbon dioxide laser marking machine; 3) output laser pulse energy of a high-energy carbon dioxide laser and the period and length of a processing grating are determined, and the grating is written; and 4) one end, far from the long-period grating, of the all-solid photon band-gap fiber is cut and serves as the reflecting surface. The sensor is high in reliability and contract and compact instructure, and can be used for the sensing field, especially for field measurement in the high-temperature environment.

Description

technical field [0001] The invention relates to the field of optical fiber sensing, in particular to an optical fiber reflection probe sensor based on cladding supermode interference and a manufacturing method thereof. Background technique [0002] Optical fiber intermode interferometer is an important type of optical device in the field of optical fiber. It can not only be used to manufacture important devices such as optical fiber filters, multi-wavelength lasers, and wavelength division multiplexers, but also has a very wide range of applications in the field of optical fiber sensing. The principle of fiber-optic intermode interferometer is to adopt specific mode excitation and coupling technology. Coupling and interference occur between the core fundamental mode and the core higher-order mode or cladding mode. When the external environment changes, it will cause the drift of the corresponding spectral interference peak, so that various external physical quantities includ...

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Problems solved by technology

These interferometers have some inherent disadvantages: the diameter of the tapered interferometer is very thin, the structure is relatively fragile and easy to break, and it is easily disturbed by other external factors; the "single-mode-multimode-single-mode" intermode interferometer In order to achieve a relatively high fringe contrast, it usually causes a large insertion loss; while the cascaded grating interferometer requires high processing technology, and it is usually difficult to process grating pairs with completely consistent physical parameters, so the repeatability of this type of interferometer low and difficult to manufacture

[0004] In addition, there is an intermode interferometer based on the F-P cavity. This type of cavity structure interferometer has very high requirements on the manufacturing process, which is not conducive to widespread industrial application.

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