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Fabrication of Surface Acoustic Wave Devices on Lithium Niobate
Published on: June 18, 2020
Electro-optic long-period waveguide gratings in lithium niobate
W Jin1, K S Chiang, Q Liu
1Department of Electronic Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Hong Kong, China.
Optics Express
|December 10, 2008
Summary
Researchers developed electro-optic (EO) long-period waveguide gratings (LPWGs) in lithium niobate (LiNbO3). These gratings offer tunable optical filtering and modulation for high-speed applications.
Area of Science:
- Photonics and Waveguide Technology
- Materials Science
Background:
- Lithium niobate (LiNbO3) is a key material for electro-optic (EO) devices.
- Long-period waveguide gratings (LPWGs) are essential for optical signal processing.
Purpose of the Study:
- To fabricate and characterize novel EO LPWGs in a specialized LiNbO3 waveguide structure.
- To investigate the impact of waveguide parameters and cladding modes on grating performance.
- To explore the potential for high-speed optical modulation and filtering.
Main Methods:
- Fabrication of LiNbO3 waveguides using a two-step proton-exchange process with a reverse proton-exchange cover layer.
- Experimental characterization of LPWG performance, including rejection band and thermal tunability.
- Theoretical analysis of EO grating efficiency limits.
Main Results:
- Demonstrated EO LPWGs with a 27-dB rejection band at 95 V driving voltage.
- Achieved thermal tunability of the center wavelength with a sensitivity of -0.4 nm/°C.
- Identified potential for improved efficiency through optimized waveguide and electrode designs.
Conclusions:
- The developed LiNbO3 LPWGs offer both EO control of grating strength and thermo-optic control of wavelength.
- These devices present significant opportunities for high-speed dynamic optical filtering and intensity modulation.
- Further optimization can lead to enhanced performance for advanced photonic applications.
