Date of Award
Spring 2024
Document Type
Dissertation
Degree Name
Doctor of Philosophy (PhD)
Department
Electrical Engineering (ENAS)
First Advisor
Tang, Hong
Abstract
The increasing demanding for digital information processing capability presents significant challenge interms of energy consumption in big data centers and could servers. This high energy consumption results from the energy-intensive nature of CMOS-based CPU and GPU chips, which drives researchers to explore alternative computing platforms. Among them, cryogenic computing based on superconducting electronics is one of the most promising technologies, which includes rapid single flux quantum (RSFQ) circuits for classical computing and superconducting quantum circuits for quantum computing. Fulfilling the superiority these cryogenic computation schemes promise, whether classical or quantum, relies on the development toward large-scale superconducting integrated circuits (ICs). A fundamental roadblock on this scaling roadmap is their connectivity to room-temperature electronics, which has so far relied on coaxial cables that have limited bandwidth, bulky size and finite thermal conductivity. All these factors have limited the scalability of the current superconducting ICs far below the desired level. To address this challenge, photonic links using optical fibers have been identified as a promising solution. Compared to electrical cables, optical fibers offer two orders of magnitude lower heat load and three orders of magnitude higher bandwidth. However, a crucial component for implementing the optical fiber-based signal link is missing: cryogenic electro-optic modulators (EOMs), the development of which has been stifled by the stringent requirements of superconducting circuits, in terms of cryogenic compatibility and the infinitesimal signals to be uplifted. This thesis addresses this critical gap in cryogenic photonic links by developing electro-optic modulators(EOMs) capable of optically reading out superconducting ICs. Our innovation lies in superconducting electro-optic modulators (SEOMs). We firstly present the concept, working principle and our development process of SEOM. We then demonstrate that our SEOM breaks the fundamental performance tradeoff in conventional EOM and achieve a two-order-of-magnitude lower and three- order-of-magnitude higher transduction efficiency, setting the new world-record in traveling-wave EOM. In the end, we demonstrate cryogenic-to-room-temperature data egress using our SEOM, including the first direct photonic readout of an RSFQ circuit. We believe our work in this thesis presents a viable solution toward high-bandwidth signal transfer between future large-scale superconducting ICs and room-temperature electronics.
Recommended Citation
Shen, Mohan, "Superconducting Electro-optic Modulator for Cryogenic Data Egress" (2024). Yale Graduate School of Arts and Sciences Dissertations. 1288.
https://elischolar.library.yale.edu/gsas_dissertations/1288
