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Updated: Jan 22, 2026
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Fabrication of Surface Acoustic Wave Devices on Lithium Niobate
Published on: June 18, 2020
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High coupling efficiency grating couplers on lithium niobate on insulator
Optics Express
|June 30, 2019
Summary
We developed new grating couplers on lithium niobate for efficient light coupling between optical fibers and waveguides. These devices offer high coupling efficiency for both TE and TM polarized light, enabling more compact photonic designs.
Area of Science:
- Photonics and Materials Science
- Integrated Optics
- Lithium Niobate Photonics
Background:
- Efficient vertical coupling is crucial for integrated photonic circuits.
- Lithium niobate on insulator (LNOI) offers excellent optical properties but requires effective interfacing.
- Existing coupling methods can be complex or inefficient.
Purpose of the Study:
- To demonstrate monolithically defined grating couplers in Z-cut LNOI.
- To achieve high coupling efficiency for both TE and TM polarized light.
- To investigate taperless designs for miniaturization.
Main Methods:
- Fabrication of grating couplers directly on Z-cut LNOI substrates.
- Characterization of coupling efficiency using optical fiber alignment.
- Design and analysis of taperless grating structures.
Main Results:
- Monolithically defined grating couplers achieved high coupling efficiencies.
- Demonstrated coupling efficiencies of ~44.6% for TE and ~19.4% for TM polarized light.
- Taperless designs were explored for reduced device footprint.
Conclusions:
- Efficient grating couplers can be fabricated directly on LNOI.
- The demonstrated devices enable high-performance vertical light coupling.
- Taperless designs show promise for compact LNOI-based photonic devices.
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