We present a compact,highly tolerant vertical coupling structure,which can be a generic design that bridges the gap between conventional resonant couplers and adiabatic couplers for heterogeneously integrated devices....We present a compact,highly tolerant vertical coupling structure,which can be a generic design that bridges the gap between conventional resonant couplers and adiabatic couplers for heterogeneously integrated devices.We show insights on relaxing the coupler alignment tolerance and provide a detailed design methodology.By the use of a multisegmented inverse taper structure,our design allows a certain proportion of the odd supermode to be excited during the coupling process,which simultaneously facilitates high tolerance and compactness.With a total length of 87μm,our coupler is almost threefold shorter than the state-of-the-art alignment-tolerant adiabatic couplers and outperforms them by demonstrating a more than 94%coupling efficiency(for<0.3 d B coupling loss)with±1μm misalignment tolerance,which,to our best knowledge,is a new record for III-V-on-silicon vertical couplers.Furthermore,our design has high tolerance to fabrication-induced structural deformation and ultrabroad bandwidth.These features make it particularly suitable for building densely integrated III-V-onsilicon photonic circuits with commercially available microtransfer printing assembly tools.The proposed design can be widely adopted in various integration platforms.展开更多
基金Horizon 2020 Framework Programme(101017088)Engineering and Physical Sciences Research Council(EP/T028475/1)。
文摘We present a compact,highly tolerant vertical coupling structure,which can be a generic design that bridges the gap between conventional resonant couplers and adiabatic couplers for heterogeneously integrated devices.We show insights on relaxing the coupler alignment tolerance and provide a detailed design methodology.By the use of a multisegmented inverse taper structure,our design allows a certain proportion of the odd supermode to be excited during the coupling process,which simultaneously facilitates high tolerance and compactness.With a total length of 87μm,our coupler is almost threefold shorter than the state-of-the-art alignment-tolerant adiabatic couplers and outperforms them by demonstrating a more than 94%coupling efficiency(for<0.3 d B coupling loss)with±1μm misalignment tolerance,which,to our best knowledge,is a new record for III-V-on-silicon vertical couplers.Furthermore,our design has high tolerance to fabrication-induced structural deformation and ultrabroad bandwidth.These features make it particularly suitable for building densely integrated III-V-onsilicon photonic circuits with commercially available microtransfer printing assembly tools.The proposed design can be widely adopted in various integration platforms.
