Research On Crosstalk Characteristics Based On Polymer Micronano Fiber Crossover Structure

The rapid development of nanoscience and nanotechnology has contributed to a significant increase in the demand for higher integration density of photonic devices and integrated circuits,prompting people to continuously explore ways to break the limit of device size.Therefore,ultra-compact and complex photonic devices and miniaturized integrated optical circuits have become hot spots in the field of photonics research.Polymermicro-nano fiber(PMNF)has been widely used in the construction of miniaturized integrated optical circuits and ultra-compact photonic devices because of its excellent capability of device construction,light conduction and unique mechanical properties,as well as good flexibility and elasticity.However,the crosstalk generated among the densely-arranged polymer micro-nano fibers due to evanescent wave coupling has become an important issue in these applications.Therefore,it is necessary to study how to reduce the crosstalk between polymer micro-nano fibers.Based on the Finite-Difference Time-Domain Method(FDTD),the crosstalk between two straight intersecting polymer micro/nano fibers is systematically studied in the three-dimensional space.Moreover,two kinds of bridge-type polymer micro/nano fiber cross structures are designed,and the crosstalk generated by them is analyzed and researched in detail.The main research work and results are as follows:1.Design and analysis of straight polymer micro/nano fiber cross structure: Firstly,a physical model of the cross structure based on identical polymer micro/nano fibers is established,and the effects of the cross angle,diameter,separation distance,polarization mode and near-infrared wavelength on the crosstalk are analyzed.Then,a physical model of the cross structure based on different polymer micro-nano fibers is established.The influence of different diameters and different materials on crosstalk is analyzed,that is,the influence of diameter difference and refractive index difference on the crosstalk,respectively.Finally,for the straight polymer micro-nano fiber intersecting structure composed of different materials,we studied how to achieve the lowest crosstalk by changing the core diameter.Moreover,the effect of coupling direction on the crosstalk is analyzed.The results show that the crosstalk can be effectively reduced by designing the structural parameters above.2.Design and analysis of bridge-type micro-nano fiber cross structure: Based on the research of straight polymer micro-nano fiber cross structure,the bridge-typed polymer micro-nano fiber cross structure based on cosine bending and arc bending are designed and researched for the first time.Firstly,a physical model of the bridge-type cross structure based on cosine bending is established,and the effects of the bending height,bending width and diameter of the structure on the crosstalk are analyzed.Then,a physical model of the bridge-type cross structure based on arc bending is established,and the influences of the radius of curvature,? angle and diameter of the structure on the crosstalk are analyzed.On this basis,the influence of coupling direction on crosstalk is analyzed.Finally,the above two bridge-type cross structures are compared.In addition,the bending loss caused by the bridge-type cross structure is briefly analyzed in the above research process.The results demonstrate that the crosstalk generated by bridge cross structure,even at a small cross angle,can be effectively reduced by designing the parameters studied above while taking into account the bending loss.The results provide valuable reference for the construction of ultra-compact and complex photonic devices as well as miniaturized integrated optical circuits.