arXiv subjects

Harmen Smedes

Publications and source records attributed to Harmen Smedes.

2 recordsLinked to original sources

arXiv2026

Monolithic high density integrated photonics on bulk lithium niobate

Functional electro-optic (EO) tunable photonic integrated circuits are crucial to next-generation information processing and advanced computing, where ferroelectric materials such as lithium niobate (LiNbO3) provide outstanding optical properties and versatile tuning mechanisms. However, beyond achieving high-performance devices, practical deployment of LiNbO3 photonic integrated circuits requires rapid and cost-effective scale-up, which remains challenging because of the fabrication complexity and high costs of ion-sliced thin-film lithium niobate and wafer bonding processes. To address this gap, we demonstrate a fully monolithic photonic platform, amorphous silicon carbide (a-SiC) on bulk LiNbO3 crystal substrate, enabling scalable, CMOS-compatible, low-cost, and high-density photonic integrated circuits without relying on thin-film LiNbO3. This integration approach breaks the long-standing cost-performance-scalability tradeoff, and intrinsically eliminates the need for sophisticated fabrication processes, including ion slicing, wafer bonding, and LiNbO3 etching. It realizes high-density, low-loss, and record high EO tuning efficiency of VpiL = 2.87 Vcm on bulk LiNbO3 crystal substrate. Furthermore, leveraging slow-light effect near photonic crystal bandgap, an 8.5-fold EO tuning efficiency enhancement is achieved, highlighting the platform's capability in confinement control and dispersion engineering.

physics.optics↗

arXiv2025

Heterogeneous integration of silicon nitride and amorphous silicon carbide photonics

Amorphous silicon carbide (a-SiC) has emerged as a compelling candidate for applications in integrated photonics, known for its high refractive index, high optical quality, high thermo-optic coefficient, and strong third-order nonlinearities. Furthermore, a-SiC can be easily deposited via CMOS-compatible chemical vapor deposition (CVD) techniques, allowing for precise thickness control and adjustable material properties on arbitrary substrates. Silicon nitride (SiN) is an industrial well-established and well-matured platform, which exhibits ultra-low propagation loss, but it is suboptimal for high-density reconfigurable photonics due to the large minimum bending radius and constrained tunability. In this work, we monolithically combine a-SiC with SiN photonics, leveraging the merits of both platforms, and achieve the a-SiC/SiN heterogeneous integration with an on-chip interconnection loss of 0.32$\pm$0.10 dB, and integration density increment exceeding 4,444-fold. By implementing active devices on a-SiC, we achieve 27 times higher thermo-optic tuning efficiency, with respect to the SiN photonic platform. In addition, the a-SiC/SiN platform gives the flexibility to choose the optimal fiber-to-chip coupling strategy depending on the interfacing platform, with efficient side-coupling on SiN and grating-coupling on a-SiC platform. The proposed a-SiC/SiN photonic platform can foster versatile applications in programmable and quantum photonics, nonlinear optics, and beyond.

physics.optics↗