| Optical fiber sensing technology is a technology that uses fiber strain characteristics to measure.Because of its unique long-distance monitoring,cheap engineering construction,high precision,etc.,it is applied widely in large-scale long-distance engineering projects such as aircraft,oil and gas pipeline safety monitoring,and military civil security.The erbium-doped fiber amplifier(EDFA),which is an important component of optical fiber sensing and optical communication,directly amplifies the signal in the system without photoelectric conversion.And it has many advantage such as high gain,high output power,low noise figure,independent of polarization,amplification characteristics independent of system bit rate and data format,simultaneous amplification of multiple wavelength signals,etc.,so it is applied widely in long-distance fiber optic communications and optic fiber sensing.In the field of aircraft fuel system,liquid storage and transportation,the measurement of liquid level position information is often performed,so the optical fiber liquid level sensing technology is also important in liquid fuel storage,transportation and aircraft fuel systems,and it is an important part of optical fiber sensing technology.This article analyzes the working principle and characteristics of the linear cavity structure EDFA firstly,and the linear cavity structure erbium-doped fiber amplifier is simulated through Optisystem software,and an optical system for experimental verification is builded.Then,based on this,the EDFA is optimized.In the theoretical research and optimization design of erbium-doped fiber amplifiers,this article mainly discusses the following:1.The working principle and working characteristics of the linear cavity EDFA are analyed,and the simulation experiments is carried out.On this basis,a new structure EDFA based on hybrid fiber ring cavity is proposed,and theoretical analysis and experimental verification are carried out.It can be seen from the experimental results that the EDFA based on the hybrid fiber ring cavity structure can effectively suppress the noise of the system and improve the signal-to-noise ratio of the signal light.2.The drive control circuit for erbium-doped fiber amplifier is designed,and a small-sized integrated circuit board(6×8cm~2)is fabricated,which successfully drives the EDFA to work normally and runs stably.On this basis,a metal package(7×9cm~2)is designed and fabricated,and the circuit part and the optical path part are all packaged inside to make an amplifier prototype,which can be better applied to actual engineering projects.3.The working mechanism of fiber-optic distributed sensing system is analyzed and discussed.A fiber-optic distributed sensing system based on phase sensitive optical time domain reflectometer(?-OTDR)is built and a new structure erbium-doped fiber amplifier is applied to the system.It can be seen from the experimental results that the EDFA based on the hybrid fiber ring cavity structure can effectively suppress the noise of the fiber distributed sensing system and increase the signal-to-noise ratio of the signal light by about 8 dB.4.The working principle of the tapered fiber oil level sensing sensor system is analyzed and discussed.Based on the dtive control circuit of erbium-doped fiber amplifier,the drive control circuit for the tapered fiber oil level sensing system is designed and fabricated,and the tapered fiber oil level detection sensor system was built for experiments.Through the experimental results,it can be seen that the tapered fiber oil level detecting and sensing system works stably,and the liquid level positioning accuracy of the tapered fiber oil level detecting and sensing system is high(0.4mm),which makes it has good practical value.In order to improve the reliability of the tapered fiber oil level sensing system,we designed a fiber optic oil level sensing sensor system with dual probe redundancy structure,which effectively improved the reliability of the fiber oil level sensing system. |
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