Compact, tunable microring resonator on a lithium niobate platform using etchless fabrication methods

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Ghumro, Adnan and Smith, Jack A. and McKnight, Loyd J. and Strain, Michael J. (2026) Compact, tunable microring resonator on a lithium niobate platform using etchless fabrication methods. Optics Continuum, 5 (3). pp. 800-810. ISSN 2770-0208 (https://doi.org/10.1364/OPTCON.583515)

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Abstract

Tunable microring resonators on a lithium niobate on insulator (LNOI) platform are demonstrated making use of thick polymer strip-loaded waveguides and bound states in the continuum (BIC) to achieve compact devices without plasma etching. The racetrack resonator device, with a bend radius of 94 , demonstrates strong confinement for TM-polarized modes, enabling electro-optic modulation with a modest half-wave voltage–length product of 35 . The device achieves a loaded quality factor of 4.17 × 104 for TM polarization and also supports purely linear TE modes with a loaded quality factor of 1.1 × 104 through guiding in the polymer layer. This etch-free process simplifies fabrication while maintaining access to lithium niobate’s (2) nonlinearity, offering a scalable route for photonic integrated circuits that combine reduced footprint, effective electro-optic performance with future potential for polarisation diversity on-chip.

ORCID iDs

Ghumro, Adnan, Smith, Jack A. ORCID logoORCID: https://orcid.org/0000-0002-2767-4510, McKnight, Loyd J. ORCID logoORCID: https://orcid.org/0000-0003-2121-0907 and Strain, Michael J. ORCID logoORCID: https://orcid.org/0000-0002-9752-3144;
CORE (COnnecting REpositories)