Multimode interferometer based on fiber core refractive index modulation line and preparation method thereof

Abstract

The present invention discloses a multimode interferometer based on fiber core refractive index modulation line and a preparation method thereof. In the technical scheme, laser is focused at a fiber core to allow the fiber core refractive index at the laser focusing position to change so as to form a refractive index modulation line, when light passes through the refractive index modulation line, the light is not completely trapped in the fiber core and is largely diffused to a fiber cladding so as to generate multimode interference, and when the formed fiber core multimode interferometer is changed caused by an external environment, interference fringes are changed so as to realize detection of the physical quantity. The multimode interferometer and the preparation method thereof are simple in structure, simple in manufacturing and high in stability, resist interference of the severe environment and is short in processing period and compact in structure, reaches higher sensitivity and has universal application prospects at the aspects of environment detection, biochemical sensing and the like.

Description

technical field [0001] The invention belongs to the field of optical fiber sensing, in particular to a multimode interferometer based on fiber core refractive index modulation lines and a preparation method thereof. Background technique [0002] The all-fiber multimode interferometer sensor has the advantages of simple structure, small size, light weight, anti-electromagnetic interference, chemical corrosion resistance, high sensitivity, etc., and has become a research hotspot at home and abroad. It is used in aerospace, food safety, and air quality monitoring. , Fire early warning, biomedicine and other industries have broad application prospects. As the application fields of multi-mode interferometers expand day by day, corresponding researches on various manufacturing methods of multi-mode interferometer sensors have been carried out in the prior art. At present, the production methods of all-fiber multimode interferometer mainly include: [0003] (1) Based on the fusio...

AI Technical Summary

Problems solved by technology

The taper process avoids the assembly and splicing process of components. However, the taper area is very fragile, has poor robustness, is susceptible to external disturbances and has a short service life, and uses the effect of the evanescent field, which is prone to light energy leakage and in the sensor. Applications are highly susceptible to interference from other noise types

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