Research Article

Benchmarking dual-polarization silicon nitride photonic integrated circuits for trapped-ion quantum technologies

¹ Physikalisch-Technische Bundesanstalt, Bundesallee 100, Braunschweig, 38116, Germany
² Technische Universität Braunschweig, Institute of Semiconductor Technology, Hans-Sommer-Str. 66, Braunschweig, 38106, Germany
³ Laboratory for Emerging Nanometrology (LENA), Langer Kamp 6a/b, Braunschweig, 38106, Germany
⁴ AMO GmbH, Otto-Blumenthal-Straße 25, 52074 Aachen, Germany
⁵ Chair of Electronic Devices, RWTH Aachen University, Otto-Blumenthal Str. 25, Aachen 52074, Germany
⁶ Leibniz Universität Hannover, Institut für Quantenoptik, Welfengarten 1, Hannover, 30167, Germany
⁷ Leibniz Universität Hannover, Laboratorium für Nano- und Quantenengineering, Welfengarten 1, Hannover, 30167, Germany

^* Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Received: 29 January 2026
Accepted: 26 May 2026

Abstract

Trapped ions are one of the most advanced platforms for quantum technologies, with applications ranging from quantum computing to precision timekeeping. A crucial step towards more compact and scalable systems involves integrating photonic integrated circuits (PICs) into surface ion traps to enable on-chip light delivery and optical addressing of individual ions. Currently, most implementations rely solely on transverse-electric (TE) mode grating couplers, where the emitted light is polarized in the plane of the chip. In this work, we design, fabricate and characterize key silicon nitride (Si₃N₄) PIC components required for scaling trapped-ion based quantum systems to multiple operating zones, including incoupling structures, splitters, and grating couplers that support both TE and transverse-magnetic (TM) modes with comparable optical losses. We benchmark the PIC at 760 nm, which is a typical wavelength for Yb⁺-applications. The fabricated grating couplers enable the outcoupling of collimated free-space beams for both polarizations, exhibiting distinct emission angles. This dual-polarization capability gives more flexibility in polarization control and expands the accessible optical design space for trapped-ion quantum technologies.