Research On The Photonic-bandgap Fiber Resonator Optic Gyroscope

Resonator fiber optic gyroscope(R-FOG)has become a focus of research for its excellence development prospects,whose basic working principle is to detect the resonant cavity frequency difference generated by the rotation of the completion of the measurement of the rotational angular velocity.In the R-FOG,in order to obtain better resonator performance,people often use narrow band light source,but narrow band light source has high coherence,which makes the gyro's optical noise significantly enhanced,seriously affecting the R-FOG performance.Researchers propose a variety of measures related to optical noise suppression,but the results are not very good.Hollow-core photonic bandgap fiber is a novel microstructure fiber,because of its light transmission can be achieved in air core,and the air medium compared to traditional solid core(Si/Si02)has lower optical properties in some fiber characteristics.People consider the HC-PBF used in R-FOG build HC-PBF-ROG,thereby reducing the associated noise.Although HC-PBF-ROG has potential advantages in terms of error suppression,there are still some problems at present.First,The HC-PBF,waveguide dimensions directly affect the transmission characteristics.Performed for R-FOG fiber design,how to make a specific band of light incident has the best transmission characteristics to be studied Second,the loss of HC-PBF is bigger than single mode fiber,which has effect on the use of HC-PBF.Third,there is no research on specialized HC-PBF for R-FOG.The main character of specialized HC-PBF should include lower Kerr nonlinear characteristics,Rayleigh scattering characteristics and better polarization-maintaining characteristics or single-polarization characteristics.Forth,the noise caused by the dual polarization eigenstates's crosstalk in the HC-PBF resonator.At last,the problem of discrete reflection in FOG system should be solved.Based on these previous problems,this paper starts with the design of the HC-PBF structor.A new kind of HC-PBF is contrived.Also the method of restraining the noise of polarization and discrete reflection is researched.The main work and innovation of this paper is listed as follow:1 Studied the HC-PBF transmission cutoff range characteristics.Analyzed the photonic bandgap properties of HC-PBF by using the plane wave expansion method,derived the numerical aperture of the hollow-core fiber,found that due to photonic bandgap,existence two numerical aperture extremes in the HC-PBF;study transfer characteristics of different cut-off duty cycle range,and found the duty cycle is an important factor affecting the central wavelength ratio and the ratio of the width of the wavelength;utilize HC-PBF transmission cutoff range,designed the basic structure of HC-PBF has the lowest confinement loss at 1550nm.2 HC-PBF is cauculated using full vector finite element method,by which way the intensity distributing of the surface mode around core is achieved.The influence of HC-PBF'score radius to wastage of surface mode is researched.Then it is discovered that it can restrainthe influence of the surface mode loss.3.A new dual elliptical assistant holes HC-PBF aims at R-FOG is designed by the theory of resonant coupling effect.Also the transport character of each transport mood is investigated.The result shows that the best performance of the new fiber appears around the wave band of 1550nm.Considering the main source of error,the nonlinear character and Rayleigh scattering coefficient is analysed.4.Comprehensive analysis of the HC-PBF-ROG the Kerr effect and Shupe effect.Including generating mechanism and is currently the major inhibitory measures,the results indicate that the use of hollow-core optical fiber constructed HC-PBF-ROG could effectively and significantly reducing the Kerr effect for the performance of the gyro;Shupe effect of errors in precision R-FOG also should be considered,HC-PBF-ROG hollow-core optical fiber used in the lower Shupe coefficient ring resonator with low short fiber length and wound reasonable means to significantly reduce the gyroscopic effect of errors in the Shupe.5.The advantage of HC-PBF in restraining Kerr error and Shupe error is analysed in 1he paper.The transport matrix of single polarization fiber resonator is established.Based on the transport matrix,the polarization error model of polarization fiber resonator is established using the method of Jones matrix.The theoretic analyse of the HC-PBF-ROG's polarization error shows that,the polarization error can be restrained by single polarizationfiber ring resonator.6.Studied the HC-PBF-ROG discrete back reflection noise.Analysis of the HC-PBF-ROG Rayleigh backscatter and discrete back reflection,back reflection were discrete categorized direct reflection and coupler reflection,established a complete discrete back reflection interference light intensity model.Proposed joining the phase modulation method at vacant end of coupler,analyzed the impact of the different modulation waveform,theoretically by setting reasonable modulation factor can effectively suppress discrete backreflection noise.