Silicon photonic Mach–Zehnder switches(MZSs)have been extensively investigated as a promising candidate for optical systems.However,conventional 2×2 MZSs are usually prone to the size variations of the arm waveg...Silicon photonic Mach–Zehnder switches(MZSs)have been extensively investigated as a promising candidate for optical systems.However,conventional 2×2 MZSs are usually prone to the size variations of the arm waveguides due to imperfect fabrication,resulting in considerable random phase imbalance between the two arms,thereby imposing significant challenges for further developing next-generation N×N MZSs.Here we propose a novel design toward calibration-free 2×2 and N×N MZSs,employing optimally widened arm waveguides,enabled by novel compact tapered Euler S-bends with incorporated mode filters.With standard 180 nm CMOS foundry processes,more than thirty 2×2 MZSs and one 4×4 Benes MZS with the new design are fabricated and characterized.Compared with their conventional counterparts with 0.45-μm-wide arm waveguides,the present 2×2 MZSs exhibit significant reduction in the random phase imbalance.The measured extinction ratios of the present 2×2 and 4×4 MZSs operating in the all-cross state are 27-49 dB and∼20dB across the wavelength range of∼60nm,respectively,even without any calibrations.This work paves the way toward calibration-free large-scale N×N MZSs for next-generation silicon photonics.展开更多
基金National Key Research and Development Program of China(2019YFB2203603)Zhejiang Provincial Major Research and Development Program(2021CO1199)+3 种基金National Science Fund for Distinguished Young Scholars(61725503)National Natural Science Foundation of China(61961146003,91950205)Zhejiang Provincial Natural Science Foundation(LD19F050001,LZ18F050001)Fundamental Research Funds for the Central Universities(2021QNA5002).
文摘Silicon photonic Mach–Zehnder switches(MZSs)have been extensively investigated as a promising candidate for optical systems.However,conventional 2×2 MZSs are usually prone to the size variations of the arm waveguides due to imperfect fabrication,resulting in considerable random phase imbalance between the two arms,thereby imposing significant challenges for further developing next-generation N×N MZSs.Here we propose a novel design toward calibration-free 2×2 and N×N MZSs,employing optimally widened arm waveguides,enabled by novel compact tapered Euler S-bends with incorporated mode filters.With standard 180 nm CMOS foundry processes,more than thirty 2×2 MZSs and one 4×4 Benes MZS with the new design are fabricated and characterized.Compared with their conventional counterparts with 0.45-μm-wide arm waveguides,the present 2×2 MZSs exhibit significant reduction in the random phase imbalance.The measured extinction ratios of the present 2×2 and 4×4 MZSs operating in the all-cross state are 27-49 dB and∼20dB across the wavelength range of∼60nm,respectively,even without any calibrations.This work paves the way toward calibration-free large-scale N×N MZSs for next-generation silicon photonics.
