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Updated: Aug 25, 2025

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Quasi-light Storage for Optical Data Packets
Published on: February 6, 2014
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CMOS-compatible compact optical isolator based on space-time modulated coupled resonators.
Optics Express
|October 19, 2022
Summary
This study demonstrates magnet-free optical isolation using phase-shifted time-modulations in coupled resonators. This compact, CMOS-compatible device achieves high isolation with low loss, paving the way for advanced photonic integrated circuits.
Area of Science:
- Photonics
- Optical Engineering
- Materials Science
Background:
- Optical isolators are crucial for preventing back-reflections in photonic systems.
- Existing optical isolators often rely on bulky magnetic materials or complex fabrication processes.
- Developing compact, on-chip, magnet-free isolators is a key challenge in integrated photonics.
Purpose of the Study:
- To demonstrate a novel approach for achieving high-performance optical isolation without magnetic materials.
- To engineer phase-shifted time-modulations in coupled resonators for efficient light control.
- To realize a compact and CMOS-compatible optical isolator device.
Main Methods:
- Development of a coupled mode theory model for near-field coupled resonators.
- Optimization of device performance using simulated annealing algorithms.
- Finite-difference time-domain (FDTD) simulations to validate the design in a 1D photonic crystal waveguide.
Main Results:
- Achieved magnet-free optical isolation exceeding 40 dB.
- Demonstrated low insertion loss below 1 dB.
- Verified device operation with modulation frequencies under 25 GHz.
- Proposed a silicon-based, CMOS-compatible fabrication approach.
Conclusions:
- Phase-shifted time-modulations in coupled resonators offer a viable path to compact, magnet-free optical isolation.
- The proposed photonic crystal waveguide implementation is compatible with standard silicon fabrication.
- This technology holds promise for integrated photonic circuits requiring robust optical isolation.

