发表机构
Indian Institute of Technology Bombay; IITB-Monash Research Academy, Indian Institute of Technology Bombay; OptixLog (Coupler Inc.); Tata Institute of Fundamental Research; Centre of Excellence in Quantum Information, Computation, Science and Technology (QuICST), Indian Institute of Technology Bombay（印度理工学院孟买分校; 印度理工学院孟买分校-IIT蒙纳士研究学院; OptixLog（Coupler公司）; 塔塔基础研究所; 印度理工学院孟买分校量子信息、计算、科学与技术卓越中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
针对可见光波段氮化硅光子集成回路中倏逝场不可达及拼接损耗问题，提出基于空气包层波导的PECVD平台，采用无拼接电子束光刻与金刚石刻划解理，实现低损耗、可扩展的量子与经典光子回路。
AI 中文摘要
可见光波段的氮化硅光子集成回路通常采用埋氧层上包层结构，并通过晶圆级工具进行切割，这些限制阻碍了外部集成发射器对导模的倏逝场访问。我们报道了一种基于PECVD生长的$Si_3N_4$平台，其设计围绕空气包层波导，使得倏逝场在整个器件长度上保持可访问。两个工艺要素使这种几何结构在芯片尺度上切实可行。固定束流、移动载物台的电子束光刻在5 mm芯片上以一次连续曝光写入500 nm单模波导，消除了拼接缝，而根据该高限制几何结构在635 nm波长下侧壁散射的$σ^{2}/d^{4}$标度关系，拼接缝原本会主导损耗预算。芯片切割采用笔式金刚石刻划，沿光刻图案化标记（与面内方向对准）进行，将Si(100)衬底解理，以80%的成品率获得法向偏差在$2^\circ$以内的端面。扫描电子显微镜的结构表征确认了无拼接波导几何结构和无损伤、近垂直的刻划端面；光通过端面耦合进入制造的器件，并引导至微环，通过散射成像确认了倏逝总线-环耦合，且基于侧壁粗糙度的散射损耗模型表明，在与观察到的端面和侧壁质量一致的粗糙度范围内，损耗保持较低。基于已展示的固有发射器-谐振器耦合，该平台将单片$Si_3N_4$光子学扩展到可扩展的可见光至近红外量子及经典回路。
英文摘要
Silicon nitride photonic integrated circuits for the visible band are conventionally built with a buried oxide overcladding and singulated with wafer-scale tooling, constraints that preclude evanescent access to the guided mode for externally integrated emitters. We report a PECVD grown $Si_3N_4$ platform designed around an air-clad waveguide whose evanescent field remains accessible along the full device length. Two process elements make this geometry practical at chip scale. Fixed-beam moving-stage electron-beam lithography writes 500 nm single-mode waveguides as one continuous exposure across the 5 mm chip, removing write-field stitching which, given the $σ^{2}/d^{4}$ scaling of sidewall scattering in this high-confinement geometry at 635 nm, would otherwise dominate the loss budget. Chip singulation is performed by pen-type diamond scribing along lithographically patterned markers registered to in-plane direction, cleaving the Si(100) substrate to yield end-facets within $2^\circ$ of normal at $80 \%$ yield. Structural characterization by scanning electron microscopy confirms stitch-free waveguide geometry and undamaged, near-vertical scribed facets; light is coupled end-fire into fabricated devices and guided to a microring with evanescent bus-to-ring coupling confirmed by scattering imaging, and a sidewall-roughness-dependent scattering-loss model indicates that loss remains low in the roughness regime consistent with the observed facet and sidewall quality. Building on the intrinsic emitter-resonator coupling demonstrated in, this platform extends monolithic $Si_3N_4$ photonics toward scalable visible-to-near-infrared quantum and classical circuits.
Comments23 pages, 7 figures
