Research On Characteristics Of Soft Glass Hollow Core Photonic Bandgap Fiber For 2?m Band Optical Transmission

With the rapid development of modern networks,expanding transmission capacity has become the primary task of the development of modern optical communication technology.The 2?m band belongs to the human eye band and has an atmospheric communication window,which is an area in which optical communication systems need to be developed in the future.Compared with quartz glass,soft glass material has a wider light transmission range and can be extended to the mid-infrared band,which is suitable for the 2?m band optical communication system.Hollow Core Photonic Bandgap Fiber(HC-PBGF)provides a unique light guide mode due to the existence of fiber bandgap.HC-PBGF has a flexible fiber structure,low loss,and controllable dispersion characteristics.It is a very suitable transmission medium for optical communication.In this paper,the soft glass material and HC-PBGF are combined to design and optimize the fiber structure to achieve excellent transmission characteristics for the needs of 2?m band optical communication systems.The main work of this paper is as follows:1.A 7-cell HC-PBGF is designed to simulate and analyze the characteristics of the fiber such as dispersion,mode field area,and loss limitation.Analyze the effect of relative aperture size and cladding air hole spacing on the characteristics of the fiber.For the single-mode optical communication systems of LP₀₁,LP₂₁ and LP₀₂ in the 2?m band respectively,the transmission range,dispersion,limiting loss and bending loss of the optical fiber are comprehensively considered,and suitable fiber structure parameters are given respectively.2.For the 2?m band multi-mode optical signal communication system,the 7-cell HC-PBGF chooses a relative aperture of 0.981 and a hole spacing of 9.9?m.The widest transmission band can be taken from 1996 nm to 2088 nm.Within this band,the limiting loss of the LP₀₁,LP₂₁,and LP₀₂ modes is less than 0.005 d B/km.When the minimum bending radius of this fiber is 5 cm,the minimum bending loss value is 0.00348 d B/km;the maximum bending radius of this fiber is 10 cm,and the minimum bending loss is 0.03659d B/km.3.A multi-core HC-PBGF is designed,which can achieve uniform propagation of each mode in 6 cores and can be used for multi-channel optical transmission.Then the structure parameters and bending radius of the multi-core HC-PBGF are optimized,and the appropriate fiber structure parameters are given in order for the fibers required for the 2?m band single-mode multi-channel optical communication system.4.For 2?m band multi-mode multi-channel optical transmission,the purpose of LP₀₁,LP₁₁,LP₂₁ and LP₀₂ modes can be simultaneously transmitted.When the relative pore size of the multi-core HC-PBGF is 0.95 and the spacing of the cladding air holes is 12.5?m,the multi-mode transmission is the best.The transmission band can be 1980 nm to 2090 nm.At this time,the multi-core fiber LP₀₁,LP₁₁,LP₂₁ and LP₀₂ modes have a limit loss of less than0.08 d B/km,a maximum bending radius of 15 cm,and a bending loss value of less than0.89 d B/km.