Work

Sub-wavelength grating silicon to silicon nitride interlayer couplers in commercial foundry silicon photonics

Year: 2026

Type: article

Abstract: The development of silicon photonics platforms has played a pivotal role in enabling large-scale photonic integrated circuits (PICs). Most of today's silicon photonics processes incorporate silicon nitride to realize devices requiring ultra-low loss and to leverage its unique material properties. Efficient light transport between the silicon and silicon nitride layers necessitates a compact and high-performance interlayer coupler. In this work, we utilize the tunable refractive index and dispersion properties of subwavelength grating (SWG) waveguides in the silicon layer to design compact and broadband interlayer couplers. We present analytical modeling, supported by simulations, of interlayer coupling and experimentally demonstrate proof-of-concept interlayer transitions using the GlobalFoundries 45SPCLO process.

Source: Optics Express

DOI: 10.1364/oe.583483

Authors: Uthkarsh Adya, Sajjad Moazeni

Language: English

Topic: Photonic and Optical Devices

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,270

Funders: National Science Foundation, U.S. Department of Energy

Awards: G5673750365, ENG-SEMICON: Coherent Co-packaged Optics (C2PO) using Offset-QAM Modulation, CAREER: Next-generation Optical I/O with Embedded Equalization for Disaggregated AI Computing