Design And Characteristics Of Hollow-core Antiresonant Fiber

The hollow-core antiresonant fiber(HC-ARF)is a kind of hollow-core microstructured fiber proposed in recent years,which transmits optical signal based on the principle of anti-resonance.This kind of optical fiber has characteristics such as low loss,ultra-wide transmission bandwidth,high birefringence,etc.It can be widely used in optical fiber communication,optical fiber sensing and high-power ultra-fast laser transmission.This thesis mainly focuses on the structural design and optical characteristics analysis of HC-ARF.The structural innovation of common traditional antiresonant optical fibers,and the simulation and optimization of optical fibers based on the basic idea of finite element are carried out to obtain better fiber performance,which is beneficial to the practical preparation and application of hollow-core antiresonant fibers.The main research contents include:(1)Starting from the research background and light guiding mechanism of hollow-core antiresonant fibers,the thesis briefly introduces the practical application and the research progress at home and abroad of this kind of fiber.Common numerical calculation methods to realize the simulation of microstructured fibers are discussed.The finite element method and related finite element software are used for fiber modeling,structural design and theoretical analysis.(2)A low-loss hollow-core antiresonant fiber containing high and low refractive index layers is designed.It is proposed to introduce micron-level high and low refractive index layers into the ordinary HC-ARF's cladding capillary structure.Combined with finite element analysis simulation,this fiber can achieve low loss transmission in a wide bandwidth range of 800nm to 2200nm.The confinement loss at 1060nm can be as low as4.8d B/km,which provides an effective medium for high-power laser transmission in the corresponding band.The dispersion and single-mode operating characteristics of the designed fiber are further analyzed.(3)A hollow-core antiresonant fiber with high birefringence is designed.It is proposed to introduce structures with different refractive indices and different thicknesses into the fiber cladding capillary.The analysis finds that the fiber structure composed of 4 capillaries can achieve higher birefringence characteristics.By further adding"nested"capillaries,the fiber loss can be reduced by 2 orders of magnitude.The optimized HC-ARF has a mode birefringence coefficient of 3.13×10^-4 at a wavelength of 1550nm and a confinement loss of about 0.56d B/m,which has obvious value in the application of polarization-maintaining fiber sensing.