Research On Transmission Characteristics And Application Of A New Hollow Core Anti-resonant Fiber

Hollow-core anti-resonant fiber（HC-ARF）is a type of hollow-core fiber,which can confine light transmission in an air core by the anti-resonant effect.Compared with solid core quartz fiber,it has the unique advantages of low confinement loss,low non linearity,low delay and high damage threshold.In contrast to hollow-core photonic bandgap fiber（HC-PBGF）,HC-ARF has simpler structure,larger transmission window,lower transmission loss and higher damage threshold and so on.At present,HC-ARF is widely used in data transmission,high power laser,nonlinear optics,fiber sensing and other fields.Therefore,it is of great significance to design HC-ARF with low confinement loss,large transmission window,effective single mode and low bending loss.In this paper,a new HC-ARF structure is proposed based on the single-ring non-nested structure and single-ring nested structure,adding small nested circles to a typical single-ring five-tube double-nested structure.The transmission characteristics of optical fibers are simulated by the full-vector finite element method and the boundary conditions of the perfect matching layer.The influence of HC-ARF core diameter D,anti-resonant tube diameter d₁,d₂,d₃,d₄,anti-resonant tube thickness t,and the number of anti-resonant tubes N on the fiber transmission performance is mainly analyzed.When the core diameter is D=50μm,d₁/D=0.8,d₂/d₁=0.28,d₃/d₁=0.35,d₄/d₁=0.25,t=0.27μm,N=5,the confinement loss of the HC-ARF at wavelength 1550nm is 0.090d B/km.In the transmission window of 1400-1580nm,the high-order mode rejection ratio can be ensured to be more than 100,and the confinement loss is less than 0.097d B/km.When the bending radius is 5cm,the bending loss is less than 11.65d B/km(2.256×10^-3d B/turn),and the dispersion value is between1.020-1.222ps/（nm·km）.The fabrication methods of HC-ARF are analyzed and compared.The novel HC-ARF can be fabricated by stacking method,and the influences of the fabrication tolerance of fiber structural parameters on the fiber confinement loss,single mode characteristics,bending loss and dispersion value are numerically simulated by finite element method.Based on the basic structural parameters,the effects of anti-resonant tube deformation,anti-resonant tube collapse and anti-resonant tube migration on the properties of optical fiber are studied emphatically.The allowable fabrication tolerances of the fiber are obtained by numerical analysis,with the anti-resonant tube deformationβbetween 0.95-1.05,the anti-resonant tube collapse H between 0-0.81μm,and the anti-resonant tube position offsetθbetween 0-6°.In this paper,we add small nested anti-resonant tube at the gap of HC-ARF large anti-resonant tube to enhance the fiber transmission performance with certain preparation tolerance,which can be applied to dense wavelength division multiplexing fiber transmission and fiber to the home applications.