Rheological Forming Analysis And Device Research Of Fused Biconical Twisted Optical Fiber

Fused optical fiber coupler is a kind of optical passive device widely used in optical fiber communication system.It is widely used in optical fiber communication,optical fiber sensing,medical treatment,and national defense ocean and so on.Fused biconical taper technolgy(FBT)is the common method to fabricate optical fiber couplers and other optical devices.In this paper,the process of fused twist-biconical taper is simulated based on optical fiber material of elastic-viscoplastic model,and the design and analysis of fused twist-biconical taper device are presented.It provides a new way to fabricate optical fiber coupler by process of fused twist-biconical taper.Firstly,the geometrical model of the deformation zone of a single optical fiber is constructed,and the geometrical model of two fiber coupling zones is analyzed.The fiber model of fused twist-biconical taper was established to determine the effect of axial torsional motion and axial torsion on the splitting ratio in the fiber coupling region.Based on the rheological properties and physical model of fiber materials,the elastic-viscoplastic model was used to describe its rheological properties,and the constitutive equations of optical fiber materials were constructed from the perspective of fiber creep.Secondly,the two-fiber fused twist-biconical taper process is analyzed from the coupling field to determine the thermo-mechanical coupling process.The fused twist-biconical taper process requires two-part simulation: the temperature field distribution in the fiber preheating stage and the simulation of the rheological process of the molten torsional tapered cone.By analyzing the temperature field in the preheating stage,the preheating time is about 30 s ~ 40 s,and the temperature distribution along the axial and radial directions can be determined.The finite element software is used to simulate the process of two fiber fused twist-biconical taper together.The angular velocity is 0.1rad / s,0.05 mm / s,0.1mm / s,0.15 mm / s,respectively.The change of the conical curve under the different pulling speed of 0.2rad/ s is obtained,and the change of the radial velocity of the fiber and the length of the fused area can be obtained by increasing the angular velocity.Finally,the design of fused twist-biconical taper system of the overall program,the fiber optic torsion twist tapered device structure design,and focus on the twist device,stretching device,clamping device structure and to reverse the output shaft and stretching platform.The modal and stress analyzes were performed to avoid the occurrence of resonance phenomena and to simulate the motion between the various parts.Compared to the traditional optical clamp fixture,a new fixture is designed which make the two fibers can be better fused together.