GOALI: Hybrid Silicon-Transparent Conductive Oxide Devices for Large-Scale On-chip Wavelength Division Multiplexing Optical Interconnects

大规模并行光互连是解决片上核之间和多芯片模块内巨大带宽需求这一巨大挑战的关键。硅光子学作为目前应用最广泛的集成光子平台，必须在能量效率和带宽密度方面出类拔萃，才能满足未来极大规模光子互连的苛刻要求。该方案的目标是开发混合硅透明导电氧化物(Si-TCO)器件，特别是包括微盘在内的微环谐振器，具有前所未有的电光(E-O)可调谐性和能源效率，用于大规模片上波分复用(WDM)光互连。拟议的研究是高度跨学科的，通过证明一条将高效TCO材料与硅光子学相结合的独特途径，将对学术界、工业界和光子界产生影响。如果成功，这一目标项目将为开发用于未来极大规模片上WDM光通信的新型硅光子器件奠定坚实的基础。教育和外联活动将使研究生、本科生和K-12学生受益，并扩大未被充分代表的少数群体和俄勒冈州州立大学女学生的参与。这项研究还将促进与惠普企业和AIM光子学的工业合作，并拓宽俄勒冈州立大学(OSU)理工科学生的研究经验。技术：TCO材料近年来在集成光子器件、超材料和超表面方面吸引了越来越多的研究兴趣，因为通过氧空位掺杂或电门控实现了非凡的折射率调节。此外，利用直流或射频溅射技术可以在不同的平台上沉积高质量的TCO材料，并且具有长期稳定性。因此，TCO材料与硅光子学完全兼容，并具有与现有硅光子集成电路(PIC)集成的潜力。该项目将专注于开发金属氧化物半导体(MOS)电容驱动的有源硅TCO光子器件，并探索与现有硅光子平台可扩展集成的可行性。这项研究的主要目标包括：1)展示具有极大电光调谐效率的混合型Si-TCO微环滤光器，以补偿制造误差和温度变化，而无需任何加热器；2)利用双功能微环谐振器实现非热片上4通道WDM发射器模块，其可同时用作波长可调谐滤光器和高速E-O调制器；以及3)验证工艺兼容性以及与硅光电子的混合集成，以便利用AIM Photonics代工服务实现未来可扩展的制造。我们预计，波长调谐功率接近于零的电调谐硅微环谐振器将取代几十年来一直使用的耗电的热加热器。最重要的是，我们将证明，这种可扩展的MOS驱动的光子器件可以通过结合AIM Photonics的无源绝缘体上硅多项目晶片(SOI-MPW)运行和俄亥俄州立大学的内部TCO工艺来制造。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Large-scale parallel optical interconnects hold the key to resolving the grand challenge of enormous bandwidth requirement between on-chip cores and within multi-chip modules. Silicon photonics, which is the mostly available integrated photonic platform, must excel in energy efficiency and bandwidth density in order to meet the stringent requirement of future extreme-scale photonic interconnects. The goal of this GOALI proposal is to develop hybrid silicon-transparent conductive oxide (Si-TCO) devices, especially microring resonators including microdisks, with unprecedented electro-optic (E-O) tunability and energy efficiency for large-scale on-chip wavelength division multiplexing (WDM) optical interconnects. The proposed research is highly interdisciplinary and will impact academia, industry, and photonics community by proving a unique path to integrate highly efficient TCO materials with silicon photonics. If successful, this GOALI project will lay a solid foundation toward developing a new type of silicon photonic devices for future extreme-scale on-chip WDM optical communication. The education and outreach activities will benefit graduate, undergraduate and K-12 students, and broaden the participation of under-represented minorities and women students at OSU. This research will also promote industrial collaboration with Hewlett Packard Enterprise and AIM Photonics, and broaden the research experiences of students in science and engineering at Oregon State University (OSU).Technical: TCO materials have attracted escalating research interests in integrated photonic devices, metamaterials and metasurfaces in recent years due to the extraordinary refractive index tuning achieved either through oxygen vacancy doping or electrical gating. In addition, TCO materials can be deposited with high quality using DC- or RF-sputtering on various platforms, which also possess long-term stability. Therefore, TCO materials are fully compatible with silicon photonics and has the potential to be readily integrated with existing silicon photonic integrated circuits (PICs). This GOALI project will focus on the development of metal-oxide-semiconductor (MOS) capacitor-driven active silicon-TCO photonic devices as well as exploring the feasibility of scalable integration with existing silicon photonic platforms. The main objectives of this research include: 1) demonstrating hybrid Si-TCO micro-ring filters with extremely large E-O tuning efficiency to compensate fabrication errors and temperature variation without any thermal heater; 2) implementing an athermal on-chip 4-channel WDM transmitter module using dual-functional microring resonators, which can simultaneously function as wavelength tunable filters and high speed E-O modulators; and 3) verifying process compatibility and hybrid integration with silicon photonics for future scalable manufacturing using AIM Photonics foundry service. We expect that the electrically tunable silicon microring resonators with near-zero wavelength tuning power will replace the power-hungry thermal heaters that have been used for decades. Most importantly, we will prove that such scalable MOS-driven photonic devices can be fabricated by combining AIM Photonics passive silicon-on-insulator multi-project wafer (SOI-MPW) runs and in-house TCO processes at OSU.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.