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Published on: September 5, 2019
An integrated multi-THz tunable linear isolator based on electro-optic non-reciprocal strong coupling
Gwan In Kim1, Violet Workman2, Oğulcan E Örsel1
1Department of Electrical & Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
Nature Communications
|July 20, 2026
Summary
This study introduces a compact electro-optic (EO) optical isolator that achieves strong coupling for the first time in EO devices. This breakthrough enables high isolation and tunable operation with minimal sidebands.
Area of Science:
- Photonics
- Integrated Optics
- Materials Science
Background:
- Optical isolators are crucial for laser systems, but existing non-magnetic designs face challenges with sidebands, bandwidth, and practicality.
- Previous approaches relied on acousto-optic (AO) or electro-optic (EO) modulation, with limitations in achieving strong coupling for enhanced performance.
Purpose of the Study:
- To demonstrate a novel compact EO optical isolator.
- To achieve the non-reciprocal strong coupling regime using electro-optics for the first time.
- To address limitations of existing isolators, including sideband generation and tunability.
Main Methods:
- Utilized thin film lithium niobate for device fabrication.
- Engineered a device architecture to achieve non-reciprocal strong coupling.
- Investigated the operational characteristics, including isolation, linearity, and tunability.
Main Results:
- Demonstrated the first EO device to reach the non-reciprocal strong coupling regime.
- Achieved a very high isolation figure of merit with linear operation and negligible sideband generation.
- Showcased THz-scale (8 nm) tunability of the isolation band, with potential for multi-THz operation.
Conclusions:
- The developed compact EO optical isolator represents a significant advancement in integrated photonics.
- The non-reciprocal strong coupling regime offers a pathway to overcome previous limitations in EO isolator performance.
- This technology holds promise for improved laser protection and signal routing applications.
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