Photonic crystal fibre-optical air chamber active cavity absorption-type gas detection device

Abstract

The invention relates to the field of fibre-optical sensing and fibre-optical gas detection. The invention aims to solve a problem that in a trace quantity detection of gas pollutant, a fibre-optical gas detection technology has difficulty in detecting and low detection sensitivity due to small ammonia gas absorption coefficient in ammonia gas detection, and also problems of short absorption distance and low detection sensitivity of a one way air chamber due to restriction by gas pool length and weak stability of a long-distance air chamber due to complex optical configuration of the air chamber. A technical scheme of the invention is as below: the photonic crystal fibre-optical air chamber active cavity absorption-type gas detection device comprises a 980 nm semiconductor laser 1, a 980 / 1550 nm wavelength division multiplexing 2, an Er-doped fiber 3, a hollow photonic crystal fiber 4, a fibre-optical reflector 5, a tunable fiber grating 6 and a fibre-optical power meter 7. The invention is mainly applied to fibre-optical gas detection.

Description

technical field [0001] The invention relates to the fields of optical fiber sensing and optical fiber gas detection, in particular to a photonic crystal optical fiber gas chamber active inner cavity absorption type gas detection device. Background technique [0002] In the process of industrial production, timely and accurate monitoring, forecasting and automatic control of flammable, explosive, toxic and harmful gases have become one of the important problems to be solved in the current coal, petroleum, chemical, electric power and other industries. Based on the gas spectral absorption method, the detection of gas concentration using the low loss window (1-2 μm) of silica optical fiber has gained widespread attention. In this band, many polluting gases or toxic gases are found, such as acetylene (C 2 h 2 ), methane (CH 4 ) and carbon monoxide (CO), ammonia (NH 3 ) and other gases have absorption lines. Among them, ammonia gas is one of the common air pollutants in indu...

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Problems solved by technology

[0005] In order to overcome the deficiencies of the existing technology, in the trace detection of gas pollutants, the fiber optic gas detection technology has a small ammonia absorption coefficient in the ammonia gas detection, which makes the detection difficult and the detection sensitivity is low; solves the difficulty of the traditional absorption type fiber optic ammonia gas In the detection technology, the one-way gas chamber is limited by the length of the gas pool, resulting in short absorption distance and low detection sensitivity, and the long-range gas chamber has disadvantages such as complex optical structure and poor stability in the gas chamber.

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