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 87 μm,our coupler is almost threefold shorter than the state-of-the-art alignment-tolerant adia-batic couplers and outperforms them by demonstrating a more than 94％coupling efficiency(for＜0.3 dB cou-pling loss)with±1 μm 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-on-silicon photonic circuits with commercially available microtransfer printing assembly tools.The proposed design can be widely adopted in various integration platforms.

CHUNHUI YAO;QIXIANG CHENG;GüNTHER ROELKENS;RICHARD PENTY

Centre for Photonic Systems,Electrical Engineering Division,Department of Engineering,University of Cambridge,Cambridge CB3 OFA,UK;Department of Information Technology(INTEC),Photonics Research Group,Ghent University-imec,9052 Ghent,Belgium

光子学研究（英文）

[1]CHUNHUI YAO;QIXIANG CHENG;GüNTHER ROELKENS;RICHARD PENTY-.Bridging the gap between resonance and adiabaticity:a compact and highly tolerant vertical coupling structure)[J].光子学研究（英文）,2022(09):2081-2090

multisegmented,supermode,adia,batic,ultrabroad,microtransfer

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