Title: The Best Reciprocal Resonators Make the Best Non-Reciprocal Systems

Abstract

Circulators are key building blocks in next generation microwave systems for Simultaneous Transmit and Receive Radios and Quantum Computers. State-of-the-art circulators have a ferro-magnet that breaks reciprocity but is hard to scale down to sub-mm dimensions for integrating with on-chip electronics. The need is even more pressing in photonic integrated circuits where it is essential to isolate the laser from reflections of downstream components. Over the last few years there has been outstanding theoretical and experimental progress in ferrite-free RF and optical non-reciprocal technologies. In this talk I will convince you that in order to build superb non-reciprocal systems, all you need is a design library, a foundry technology and generous collaborators. I will demonstrate a RF circulator built using Broadcom's film bulk acoustic resonators (FBAR) and highlight the advantages of mechanical mode coupling that help us achieve excellent power handling and bandwidth. In the second half of the talk, I will show how we leverage HBARs (the FBAR's forefather?) to modulate optical ring resonators and demonstrate optical isolation. If time permits, I will conclude my talk by providing a glimpse of how we are leveraging these technologies to achieve coherent quantum transduction between qubits, acoustic phonons and flying photons. 

The presented results are from very close collaborations with Dr. Rich Ruby’s group at Broadcom, Professor Tobias Kippenberg’s group at EPFL and Professor Greg Fuchs’ group at Cornell.

Bio:

Professor Sunil Bhave received the B.S. and Ph.D. degrees from Berkeley in EECS in 1998 and 2004 respectively. In April 2015, he joined the department of Electrical and Computer Engineering at Purdue University where he is currently the Associate Director of Operations of the Birck Nanotechnology Center. Sunil received the NSF CAREER Award in 2007, the DARPA Young Faculty Award in 2008, the IEEE Ultrasonics Society’s Young Investigator Award in 2014 and the Google Faculty Research Award in 2020.

His students have received Best Paper Awards at MEMS 2021, IFCS 2021, IFCS 2020, IEEE Photonics 2012, Ultrasonics 2009 and IEDM 2007. Before joining Purdue, Sunil was an associate professor at Cornell and sensor architect at Analog Devices.