Wavelength division multiplexer

Abstract

The invention discloses a wavelength division multiplexer, which belongs to the field of optical fiber sensor, and comprises four ports arranged on a shell, and two double-fiber collimators, two single-fiber collimators and four wavelength division multiplexing filters, which are arranged in the shell, wherein the two double-fiber collimators are connected by one of the respective tail fibers of the two double-fiber collimators, and the other respective tail fibers of the two double-fiber collimator are connected to the two ports among the four ports; the tail fibers of the two single-fiber collimators are connected to the rest two ports among the four ports respectively; two anti-stokes-wavelength wavelength division multiplexing filters among the four wavelength division multiplexing filters are spaced and arranged at an included angle between a double-fiber collimator and a single-fiber collimator; and the other two anti-stokes-wavelength wavelength division multiplexing filters are spaced and arranged at an included angle between the other double-fiber collimator and the other single-fiber collimator. The insulation degree of the device is high, and the device can be formed into a distributed optical fiber temperature sensor and can improve the temperature resolution of a system.

Description

technical field [0001] The invention relates to a wavelength division multiplexing device, in particular to a wavelength division multiplexing device used for a distributed optical fiber temperature sensor, and belongs to the technical field of optical fiber sensors. Background technique [0002] Since J.P.Dakin and others first successfully realized the distributed temperature measurement technology based on Raman scattering in 1985, people have carried out extensive research on various technologies for realizing distributed optical fiber temperature sensing. Sensing technology has been the most widely used in practice. Compared with traditional sensors, distributed optical fiber temperature sensors have many excellent advantages: using optical fiber itself as the sensing medium, temperature information of thousands of points distributed along the optical fiber can be obtained in one measurement, which realizes continuous distributed measurement and reduces the Measurement...

AI Technical Summary

Problems solved by technology

First of all, this wavelength division multiplexing device uses a 1X3 bidirectional coupler, which will introduce an additional loss of about 9.5dB (10log(1 / 9)=9.5dB), which greatly weakens the available anti-Stokes light and Stokes light intensity; Secondly, the isolation of the device is difficult to exceed 40dB, unless a very special filter is designed, the reason is the same as above

[0007] If the above-mentioned conventional wavelength division multiplexing device is used in a distributed optical fiber temperature sensor, usually due to insufficient isolation, it will cause mutual crosstalk between anti-Stokes light and Stokes light, and interference of Rayleigh scattered light, In this case, it is difficult to obtain accurate temperature information and high resolution. In severe cases, the temperature curve may even be distorted, and the system cannot work normally.

Images