Design And Study Of Silicon-Based Power Splitters Based On Direct-Binary-Search Algorithm

In the era of big data,the high requirements of communication system are put forward for the storage,processing and transmission.Photonic integrated circuits on silicon chip are gaining more and more favor because of the advantages of small size,low loss,multi-function,broad bandwidth,anti-interference,compatibility and so on.The optoelectronic hybrid integrated system has become the development trend in the future.As one of the fundamental building elements for optical network,power splitter can realize the power sharing in multiple channels,which is widely used to process optical signal on chip.However,the photonic device,realized by traditional method searching a small number of design parameters,has a large size that is not conducive to the high-density photonic integrated circuit.What is more,the traditional design process is nondirectional and time-consuming.With the improvements of computer technology and micro-nano processing technology,inverse design comes into being.Inverse design algorithms can search the device structure in full parameter space to design nanophotonic devices with the advantages of small size,low loss and multi-function.In order to further broaden the functions of the power splitters,in this paper the power splitters with novel functions are simulated by using inverse design algorithms.Considering the current situation of single-output direction,irreversible operation,single function and being untuned of power splitter,we propose the corresponding effective schemes.(1)Based the direct binary search algorithm,arbitrary-direction and multichannel power splitters are proposed.Their advantage is that the propagation direction of light on the chip can be directly changed by the low-loss and compact power splitter,without adding additional waveguide bend.(2)Based on high symmetric structure,we propose the arbitrary-input and ultra-compact 1×2 and 1×3 power splitters by utilizing the direct binary search algorithm.These devices can realize the function of power splitting,when the light source is launched from arbitrary port.This is a potential way for the irreversible power splitter.(3)Based on a rotatable direct-binary-search algorithm,the multi-function 1×2 mode converters are proposed,which can simultaneously achieve power splitting and mode conversion.The idea of this algorithm is to add a calculation of rotational dimension,which can increase search freedom and improve device performance.(4)A series of single-mode,dual-mode and three-mode nanophotonic waveguide switches are simulated by first combining direct-binary-search algorithm with phase change material.More importantly,these devices realize switching function directly in waveguides without additional design areas.Thus,the waveguide switches can be used in the waveguides of power splitter to realize the tunable function,which provides a new way for photonic interconnection network to be conveniently applied to future communication devices.Based on the inverse design algorithm,all kinds of novel silicon-based power splitters are simulated,which effectively made up for the defects of the current power splitter,such as single-output direction,irreversible operation,single function and being untuned.Moreover,our work provides theoretical guidance for the realization of nanophotonic devices and high-density photonic integrated circuits.