Mach-Zehnder interferometer in fiber based on waveguide inscribing through femtosecond laser

Abstract

The invention provides a Mach-Zehnder interferometer in fiber based on waveguide inscribing through femtosecond laser. The Mach-Zehnder interferometer comprises a broadband light source, a sensor and a spectrum analyzer. The sensor is formed in a way that the waveguides are inscribed through femtosecond laser in a single-mode fiber. The Mach-Zehnder interferometer is characterized in that the three segments successively connected waveguides inscribed by the femtosecond laser in the single-mode fiber and a fiber core form a trapezoid-shaped structure; the first segment of the waveguide is an inclined line with an included angle of 1.20 with the fiber core; the second segment of the waveguide is a cross line parallel to the fiber core; the third segment of the waveguide is an inclined line with an included angle of 1.20 with the fiber core; after the structure of the three segments of the waveguides are inscribed, the light of the fiber core will be coupled out by the first segment of the waveguide, then transmitted along the second segment of the waveguide and then coupled back to the fiber core by the third segment of the waveguide; light of the broadband light source is transmitted to the spectrum analyzer through the sensing head, so the Mach-Zehnder interferometer is formed; wavelength drifting quantity of transmittance spectrum characteristic peaks is measured, so the value of a to-be-measured environment parameter can be calculated. The Mach-Zehnder interferometer is characterized by simple preparation, low cost, small size and high flexibility, and can be used for measurement of temperature and strain.

Description

technical field [0001] The invention provides an in-line Mach-Zehnder interferometer based on a femtosecond laser writing waveguide, which belongs to the optical fiber sensing technology. Background technique [0002] Compared with traditional sensors, optical fiber sensors have extremely high sensitivity and resolution, wide frequency band range, large dynamic range, and no electromagnetic field interference. It has been practically applied in medical and other scientific research fields. The development trend of sensors is sensitive, precise, adaptable, compact and intelligent. Among many fiber optic sensors, fiber optic sensors based on Mach-Zehnder have developed rapidly and become an important branch of fiber optic sensor research. Safety detection can also be used to monitor the curing state of composite materials, etc. It is of great significance for the safe use and integrity testing of aircraft, ships, buildings, etc. As one of the important parameters of produc...

AI Technical Summary

Problems solved by technology

For the first structure, its sensitivity needs to be improved; the writing process of fiber grating is complicated, the cost is high, and the instability of its structure limits its application to a certain extent; the device made of special optical fiber has a significantly higher cost

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