A method for measuring temperature of a dual-pass mz structure fused with long-period fiber gratings

Abstract

The present invention provides a method for measuring the temperature of a double-pass MZ structure fused with a long-period fiber grating. The temperature measurement method includes the following steps: a. Lap the double-pass MZ structure. The double-pass MZ structure includes a light source, a first An optical coupler, a second optical coupler, and a first optical fiber, a second optical fiber, a third optical fiber, and a fourth optical fiber; b, fusing a long-period fiber grating into the dual-pass MZ structure, in which a long-period optical fiber will be inscribed The two ends of the optical fiber of the grating are respectively fused with the third optical fiber and the fourth optical fiber, and the long-period fiber grating constitutes the reflection end of the double-pass MZ structure; In the box, change the temperature of the temperature control box, and use a spectrometer to monitor the wavelength movement; d, draw a relationship curve between wavelength and temperature change, and use the relationship curve to measure the temperature to be measured. The invention can effectively reduce the width of the transmission peak and improve the measurement accuracy.

Description

Technical field [0001] The invention relates to the technical field of optical fiber measurement, in particular to a method for measuring temperature in a double-pass MZ structure fusion splicing long-period fiber grating. Background technique [0002] Fiber gratings are very important in the research and application of fiber lasers and fiber sensing. Fiber gratings with a grating period of tens to hundreds of microns are called long period fiber gratings (LPFG), which are characterized by co-directional transmission. The fundamental mode of the core and the cladding mode are coupled, and there is basically no back-reflected light, which is a transmissive band stop filter. Compared with Fiber Bragg grating (FBG), the resonant wavelength and resonant intensity of long-period fiber grating are very sensitive to changes in the external environment, and have a greater temperature sensitivity coefficient. As a temperature sensor, it can be used for high temperature up to 800℃. Measur...

AI Technical Summary

Problems solved by technology

Although the grating consistency of this method is good, the cost of the mask plate is high and the flexibility of preparing long-period fiber gratings is poor.

In addition, the long-period fiber grating has a wide transmission spectrum, which is easily affected by environmental changes in actual measurement, and it is easy to cause errors in the accuracy of temperature measurement.

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