May 6 (Wed) @ 1:00pm: "Photonic Integrated Frequency Stabilized Kerr Soliton Microcombs and Application to Communications, Clocks, and Metrology," Mark Harrington, ECE PhD Defense

Location: Henley Hall, Room 1010 (Lecture Hall)
Zoom Meeting: https://ucsb.zoom.us/j/86098321333

Abstract

Dissipative Kerr Soliton (DKS) microcombs have emerged as a future solution to bring metrological optical frequency comb (OFC) capabilities into a photonic integrated platform with mass-scale fabrication benefits. Precision applications including coherent optical fiber links, ultra-low phase noise microwave generators, and atomic clocks require microcombs with low phase noise comb lines repetition frequencies, which have proven difficult to implement outside of laboratory conditions. Stabilized silicon nitride (Si3N4) DKS microcombs have emerged as a leading integration approach due to the low optical loss, compatibility with CMOS semiconductor foundry processes, and potential for higher level system-on-chip integration. These properties enable chip integrated versions of lab-scale stabilized combs, which promise to greatly reduce system cost, complexity, and power consumption while enabling a wide range of portable applications.

In this work, Si3N4 photonic waveguide resonators are employed as Brillouin laser cavities, coil resonator frequency references, and Kerr soliton generators, and are combined into a single system to generate stabilized optical frequency comb sources. Frequency noise propagation from pump laser sources to generated comb lines are investigated in both one and two-point stabilized soliton schemes, and methods enabling monolithic integration of microcombs and stabilization resonators are investigated, including laser-tuning-free soliton generation with PZT actuation and soliton-compatible microrings fabricated in a low-temperature process compatible with multilayer integration. These sources are subsequently used to demonstrate two applications: First, an ultralow fundamental linewidth laser-pumped frequency comb is used as a common source for a high capacity WDM coherent fiber link. The link leverages the frequency stability of this comb source by replacing digital phase estimation with a low-bandwidth, low power optical phase-locked loop. Second, simultaneous stabilization of a microcomb and its pump laser to a coil resonator is demonstrated using integrated PZT actuation. This fully stabilized source is then used to demonstrate ultra-low phase noise microwave generation in an architecture with greatly simplified design and reduced hardware requirements.

Bio

Mark Harrington is a PhD candidate in the department of electrical and computer engineering (ECE) at UC Santa Barbara, advised by Professor Daniel J. Blumenthal. He received his B.S. in Electrical Engineering from UC Santa Cruz in 2017. His research focuses on photonic integrated approaches to narrow-linewidth lasers, frequency combs, and optical transceivers.

Hosted By: ECE Professor Daniel Blumenthal

Submitted By: Mark Harrington <mwh@ucsb.edu>