| Because of its inherent properties of wideband, randomness and similardelta, chaos has been extensively applied in secure communication, sensor andranging. Er3+doped fiber laser has been paid much attention for low threshold,high power, high accuracy, excellent compatibility and its special wavelength.Therefore, chaotic behaviors are studied by Erbium doped fiber laser, which willshow some potential application in fiber sensing, system detection,communication, and medical field.Detection and calculation of static ice pressure have become a challengingproblem in ice mechanics research, which is related to complex materialproperties and geographical conditions. But fiber Bragg grating (FBG) has manymerits including low loss, interference resistance, corrosion resistance,distribution sensing, multi parameter sensitive and hazardous location. However,FBG has become one of the most potential sensitive elements in intelligentmaterial systems and structural health inspection. Meanwhile, FBG hasextensive application prospects in the field of military, electric power industry,environmental monitoring, biomedical and civil engineering. In this paper, according to chaotic correlation and FBG as sensing element, then the FBGsensing system based on chaotic fiber laser is established. This sensing system isstudied by theory and experimental including chaotic generation，temperaturecompensation and static ice pressure detection. The main research contents areas follows.1. Based on the operation principle of Er3+doped fiber laser, we describethe basic model and methods on chaotic generation. Then the chaotic generationis analyzed in theory and numerical simulation, utilizing the Er3+doped fiberlaser on account of Kerr effect. Chaotic dynamics are demonstratedexperimentally using Er3+doped fiber laser. Experimental results indicate thatEr3+doped fiber laser can show the doubling period route to chaotic state byadjusting pump current when polarization controller is adjusted to a fixed and anappropriate position. The experimental results are well agreed with thenumerical simulation results.2. The coupled mode theory and sensing theory of FBG are introduced. Onthe basis of the sensing condition, the multi wavelength chaos of Er3+dopedfiber laser is studied by tunable filter and chaotic correlation is improved byadding the nonlinear effect. Combination the properties of chaotic correlationand FBG sensing，we propose that four identical low reflective FBGs assensing element to detect the pressure by correlation peaks between referencelight and reflected light from FBGs to locate the position of FBGs. Then theFBG pressure sensing system based on Er3+doped fiber chaotic laser is designedand this sensing system is studied theoretically and experimentally. The resultsof experimental and numerical simulation present that this system and methodcan measure the pressure accurately, which show the effectiveness.3. According to the linear relation between resistance and temperature ofPt100, as well as stability of Pt100in low and high temperature, we design the temperature compensation circuit with high accuracy. In circuit, Pt100is as atemperature sensitive component and MSP430is as the data processing center.Experimental research shows that measurement error to temperature oftemperature compensation circuit is smaller than0.1℃. The temperaturedetection system is designed according to the basic philosophy of the low powerdesign, and is suitable to special conditions such as low temperature, noindustrial power supply.4. Based on above researches, FBG pressure sensing system based on Er3+doped fiber chaotic laser is used to detect the static ice pressure. Through thetemperature compensation, the relation between static ice pressure and FBGwavelength is achieved when the temperature is at10℃～3.5℃, whichprovides a new measuring method to static ice pressure and to prepare thesensing equipment. |
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