Jun 20 (Fri) @11 AM: "Anneal-Free Ultra-low Loss Silicon Nitride Integrated Photonics For Monolithic Integration," Debapam Bose, ECE PhD Defense

Location: Engineering Science (ESB) Room 1001 (Ground floor conference Room)
Zoom Meeting : https://ucsb.zoom.us/j/84907371231?pwd=cloq2z4YNPnWmFx1ORKxzaiWpeAtri.1

Abstract

Heterogeneous and monolithic integration of the versatile low-loss silicon nitride platform with lower-temperature compatible materials such as silicon electronics and photonics, III–V compound semiconductors, lithium niobate, organics, and glasses has been inhibited by the need for high-temperature annealing as well as the need for different process flows for thin and thick waveguides. New techniques are needed to maintain the state-of-the-art losses, nonlinear properties, and CMOS-compatible processes while enabling this next generation of 3D silicon nitride integration. In this talk, we will report a significant advance in ultra-low loss linear and nonlinear silicon nitride integrated photonics, demonstrating a similar anneal-free fabrication process with a maximum oxide and nitride deposition temperature of 250 °C, for an order of magnitude range in thickness from thin ultra-low loss waveguides to thick nonlinear waveguides, without requiring stress mitigation and chemical mechanical polishing, by using inductively coupled plasma-plasma enhanced chemical vapor deposition (ICP-PECVD) for both silicon nitride and oxide growths. We achieve record-low 1.77 dB/m of loss with an intrinsic Q of 14.9 million at 1550 nm wavelength for 80 nm thin core waveguides, and 8.66 dB/m loss with 4.03 million intrinsic Q for 800 nm thick core nitrides. We demonstrate laser stabilization with over 4 orders of magnitude frequency noise reduction using a thin nitride reference cavity. Our thick nitride devices demonstrate anomalous dispersion and a near-record two-octave plus supercontinuum generation from 650 nm to 2.7 μm, as well as four-wave mixing parametric gain, with the lowest reported Optical parametric oscillation (OPO) threshold per unit length of resonator of 15.2 mW/mm for low temperature silicon nitride processes.

Bio

Debapam Bose is a PhD candidate in the OCAQpi group at UC Santa Barbara, advised by Daniel J. Blumenthal. His research has spanned from ultra-low loss waveguide fabrication to PIC-based external cavity lasers.

Hosted By: ECE Professor Daniel J.Blumenthal

Submitted By: Debapam Bose <dbose@ucsb.edu>