Temperature and strain test method based on LPFG (long period fiber grating) and thin core optical fiber

A technology of thin-core fiber and fiber grating, which is applied in the field of temperature and strain testing based on long-period fiber grating and thin-core fiber, and can solve the problem of large reflection loss

CN106767488AInactive Publication Date: 2017-05-31BEIJING INFORMATION SCI & TECH UNIV
2 Cites 21 Cited by

Patent Information

Authority / Receiving Office
CN · China
Current Assignee / Owner
Publication Date
2017-05-31
Estimated Expiration
Not applicable · inactive patent

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

The invention provides a temperature and strain test method based on LPFG (long period fiber grating) and thin core optical fiber. The method comprises the following steps that the LPFG is inscribed in the fine core optical fiber by a femtosecond laser direct writing method; a Mach-Zehnder structure formed by the fine core optical fiber inscribed with the LPFG and an ordinary single mold optical fiber (SMF-28E) through butt fusion is used for modulation on the LPFG; the change quantity of the temperature and the strain and the change matrix of the resonance peak intensity and the wave length are obtained; the wave length change value delta lambda of the Mach-Zehnder transmission spectrum resonant peak and the intensity change value delta P are detected through a spectrometer and are substituted into the change matrix to obtain the change condition of the environment temperature and the strain. The characteristic that the Mach-Zehnder transmission spectrum is modulated by the LPFG is utilized; by monitoring the wavelength and intensity change of a certain transmission resonant peak of the linear measuring region, the partition measurement of two parameters of the temperature and the strain can be realized.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention relates to a method for measuring temperature and strain, in particular to a method for measuring temperature and strain based on long-period optical fiber gratings and thin-core optical fibers. Background technique

[0002] The research and application of fiber gratings in the field of fiber lasers and fiber optic sensors is very important. Fiber gratings with a grating period of tens to hundreds of microns are called long period fiber gratings (Long period fibergrating, LPFG), which is characterized by the same direction of transmission The core fundamental mode and the cladding mode are coupled, and there is basically no back-reflected light, which belongs to the transmission-type band-stop filter. Compared with Fiber Bragg grating (FiberBragg grating, FBG), the resonance wavelength and resonance intensity of long-period fiber Bragg grating are very sensitive to changes in the external environment, and have a larger temperature sensiti...

Examples

Embodiment Construction

[0036] The objects and functions of the present invention and methods for achieving the objects and functions will be clarified by referring to the exemplary embodiments. However, the present invention is not limited to the exemplary embodiments disclosed below; it can be implemented in various forms. The essence of the description is only to help those skilled in the relevant art comprehensively understand the specific details of the present invention.

[0037] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same reference numerals represent the same or similar components, or the same or similar steps.

[0038] A temperature and strain testing method based on long-period fiber gratings and thin-core optical fibers, the method comprising the following steps:

[0039] Step 1: Write long-period fiber gratings (LPFG) on the thin-core fiber using femtosecond laser direct writing method;

[004...