一种多模干涉耦合器的性能模拟

为减小多模干涉（Multimode Interference ,MMI）耦合器件的尺寸,提出一种多模波导宽度为指数型变化的Taper结构.理论分析了多模波导长度与该Taper结构的参量之间的关系.与已被用于减小MMI器件尺寸的抛物线型Taper结构相比,该结构可进一步减小器件的尺寸.就几种波导结构参量下的MMI耦合器,利用宽角光束传播法进行了数值模拟.结果表明,指数型MMI耦合器的性能与抛物线型MMI耦合器的性能类似.指数型Taper结构可以用于MMI器件以减小该类器件的尺寸.

Properties Simulation of a Multimode Interference Coupler

A multimode interference(MMI) coupler with the exponentially tapered multimode waveguide is proposed in order to reduce the scale of the MMI device.The relation between the length of the multimode waveguide and the parameters of the tapered structure was analyzed in theory.Compared with the parabolically tapered structure,which has been successfully used in the MMI devices,this structure could further reduce the length of the MMI devices.The results of the simulation by the wide-angle finite difference beam propagation method(FD-BPM) for some MMI couplers with different parameters were given.It was shown that the performance of the MMI couplers with the exponentially tapered structure was similar to the devices with the parabolically tapered structure.As a result,the exponentially tapered structure can be used in MMI devices to reduce the length of this kind of devices.