Events Calendar

ECE PhD Dissertation: Manuj Kumar Singh

Title: Electronic-photonic mm-wave system-on-chips and passive devices in silicon CMOS photonics

Presenter: Manuj Kumar Singh

Advisor: Prof. Miloš Popović

Chair: TBA

Committee: Prof. Miloš Popović, Prof. Roberto Paiella, Prof. Rabia Yazicigil, Prof. Tianyu Wang and Prof. Vladimir Stojanović

Google Scholar: https://scholar.google.com/citations?hl=en&user=sAJcHH8AAAAJ

Abstract: Initially confined to academic laboratories, silicon photonics has emerged as a budding optical integrated circuit technology at the dawn of the 21st century. In recent years, its rapid commercialization has made several key semiconductor giants like GlobalFoundries, TSMC, Intel and IBM introducing silicon photonics processes. Concurrently, numerous enterprises and start-ups have rolled out products leveraging this technology, propelling its market value to a substantial portion of the semiconductor industry. Integrated silicon photonics has emerged as a “More-than-Moore” extension to advanced CMOS that is poised to generate high impact on numerous application domains. To realize and maximize its impact, future electronic-photonic systems-on-chip will require co-design of photonic devices and circuits, electronic designs, and CMOS foundry platforms, along with the system and application, as well possible hybrid integration of new materials.

Large mm-wave multiple-input-multiple-output (MIMO) antenna arrays enable high bandwidth beamforming applications ranging from 5G/6G communications to radar sensing. However, their efficiency depends on power scaling and tight element pitch constraints. These constraints essentially limit power dissipation, signal routing, and antenna array size-scaling. Integrated silicon photonics based mm-wave links are a promising solution to overcome such scaling constraints. In this dissertation, we present the realization of a mmwave sensing element composed of a low-noise amplifier (LNA) with photonic coupled-cavity modulators based on single and triple-rings in a monolithic CMOS process. We propose a scalable electronic-photonic solution to develop mm-wave analog photonic high-speed links connecting mm-wave antenna arrays and the remote hub with low-power and high-bandwidth density.

Another major problem with electronic-photonic integrated circuits in monolithic SOI platforms is the fluctuation of the polarization state of the input light to the chip from an optical fiber. A polarization diversity scheme comprising a polarization splitter-rotator (PSR) is desirable to implement the working of photonic devices functioning at single optical polarization. We demonstrate a compact, low cross-talk and ultra-broadband PSR based on the concepts of magic-T and rapid-adiabatic mode splitter(RAMS) in a monolithic SOI CMOS platform.

Finally, energy-efficient WDM communication links require miniaturised integrated sources producing optical frequency combs with a fixed, finite number of closely spaced (low-repetition rate, e.g. 1 to 200 GHz) comb lines. We investigate some designs related to linear configuration of coupled cavity resonators based on tri- diagonal Kac matrix enabling such cavities to support finite equi-spaced comb of resonances. Such resonator may allow designing compact and efficient cavities which decouple cavity size from comb spacings.

This dissertation demonstrates novel electronic-photonic mm-wave sensing elements operating at 57 GHz based on a LNA monolithically integrated with photonic coupled-cavity modulators based on single and triple-rings in a 45RFSOI CMOS process. We later show the first demonstration of a dual-cavity photonic molecule modulator in the Global Foundries’ 45CLO platform enabling electronic-photonic integration. We also demonstrate two types of polarization-diversity enabling devices in the monolithic SOI CMOS platform: magic-T and PSR. Finally, the concept of coupled cavity resonators with finite number of supermode resonances is presented to enable efficient finite comb generation for WDM applications.