Research On One-dimensional Periodic Dielectric Waveguide Slow Light

With the rapid development of optical fiber communication networktransmission speed and improving the speed bottleneck of the device graduallyrestricting the development of the optical network.and slow the optical waveguide issuch an effective control of the lightwave transmission structure of the groupvelocity.Formed by the Photonic crystal waveguide structure produce slow light in aroom temperature environment,exist within the photonic band gap structureand linedefects can get low group velocity,but to some extents,improving the quality of theslow light,but its also brought a very large internal reflection loss.Due to theone-dimensional periodic dielectric waveguide structure is simple,easy to preocessand easy integration with other devices in recent years has become top research.This issue designed an asymmetrical waveguide grating structure and simulatethe field distribution and calculation with the dispersion curve analysis can be drawnfrom the results of this structure in the Brillouin zone boundary flat slow light,contrastand traditional method of slow light,in turn,designed to another groove waveguidegrating slow light structure,to make it slow light by areaaway from the brillouin zoneboundary,do not exist up and down the cut-off frequency,and can effectively reducethe reflection wastage,while also compensates for slow light propagation in thegroup-velocity dispersion and increase bandwith.Concrete realization using the planewave expansion method and finite difference time domain algorithm,and to providesuch a waveguide grating broadband low dispersion slow light devices in all-opticalsignal processing,optical computing,optical sensors and non-linear enhancement toprovide a solid theoretical foundation.The main topic of the work has the following two aspects:Firstly,using the full vectorial plane-wave expansion method and finitedifference time domain(FDTD) algorithm to design and optimization of ahigh-performance asymmetric waveguide grating structure and in accordance with thestructural characteristics of the waveguide gratingstructure characteristics andboundary conditions,studied the various structural parameters(such as the period of the grating unit,the length of the waveguide,the width of the waveguide,etc)whenconditions change,the propagation constant of the nano-array,the effective refractiveindex variation,reveal the nano-arrayband structure and the inherent law of slow lightfactor,and the use of two algorithms to optimize the design during the optimizationdesign drawn after the devices in the1124nm wide spectralrange,in the Brillouin zoneboundary that normalized wave device parameter sevector of0.4252/a can beachieved relatively flat slow light.Secondly,through researching the operating wavelength the1.55m slowoptical grating-based devices,and general conclusions based on the asymetric struturebefore application of the multilayer grating coupling analysis method and the FDTDalgorithm,a one-dimensional periodic rectangular symmetry slow innovation theoptical waveguide structure the innovation a groove waveguide grating structure andthe use of highprecision theoretical research program to explore from multipleangles,slow light enhancement,from the co-existence and effectof the transverseelectric field polarized resonance analysis grating slow and light structural parameterscorresponding to the distribution characteristics of the light field,and tap the intrinsiclink between the slow light with light effective mode area,to reveal effective opticalslow light enhanced physical mechanism.The structure may be in the range away fromthe Brillouin zone,to achieve a relatively flat slow light,i.e.normalized wavevector0.352/a,can be achieved the slow light.