Refractive index sensor based on asymmetric double-core optical fiber

Abstract

The invention provides a refractive index sensor based on an asymmetric double-core optical fiber. The refractive index sensor comprises a light source, a single-mode optical fiber circulator or a single-mode optical fiber coupler, an optical fiber cone, the asymmetric double-core optical fiber, a reflection mirror and a photoelectric detection device, wherein the light source is connected with afirst port of the single-mode optical fiber circulator or the single-mode optical fiber coupler; a second port of the single-mode optical fiber circulator or the single-mode optical fiber coupler is connected with one end of the asymmetric double-core optical fiber through the optical fiber cone; a third port of the single-mode optical fiber circulator or the single-mode optical fiber coupler is connected with the photoelectric detection device; and the reflection mirror is positioned at the other end of the asymmetric double-core optical fiber. By utilizing the refractive index sensor, an integrated Michelson interferometer based on the asymmetric double-core optical fiber is formed by using characteristics that a ground mode effective refractive index of an edge core in the asymmetric double-core optical fiber is sensitive to the change of an outside refractive index and the ground mode effective refractive index of an inner core in the asymmetric double-core optical fiber is insensitive to the change of the outside refractive index, therefore, high-precision measurement for the refractive index can be realized.

Description

technical field [0001] The invention relates to an optical fiber sensor, in particular to a refractive index sensor based on an asymmetrical double-core optical fiber. Background technique [0002] Refractive index is a basic physical performance parameter of liquid, and as one of the important optical properties of matter, it plays an extremely important role in the field of optics. The measurement of the refractive index has a very wide range of applications in the fields of chemical industry, biology, pharmacy and food. Many physical or chemical parameters such as the content of a certain substance in a mixture can be obtained by measuring the refractive index. The traditional method of measuring the refractive index is the goniometric method, which is divided into two methods of measuring the minimum deflection angle and the critical angle. However, these two methods require sampling and measurement, and the measurement time is long, so it is generally not easy to reali...

AI Technical Summary

Problems solved by technology

However, the interference of the refractive index sensor based on the fiber cone occurs between the core mode and multiple cladding modes, which is multi-mode interference, and the different interference peaks in the interference spectrum have different sensitivities to the refractive index; while the microhole-based The structure requires an expensive femtosecond laser, which is expensive

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