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Fabrication And Characterization Of Photonic Crystal Slow Light Waveguides And Cavities
Published on: November 30, 2012
Novel grating design approach by radiation modes coupling in nonlinear optical waveguides
A Massaro1, R Congolani, M De Vittorio
1National Nanotechnology Laboratory of CNR-INFM, Distretto Tecnologico-ISUFI, Università del Salento, Lecce, Italy. alessandro.massaro@unile.it
Optics Express
|April 29, 2009
Summary
Radiation modes in integrated optics can enhance guided modes using tailored gratings. This study demonstrates their use in GaAs/AlGaAs waveguides for efficient second harmonic generation, improving low-intensity nonlinear processes.
Area of Science:
- Integrated optics
- Nonlinear optics
- Semiconductor device physics
Background:
- Radiation modes typically cause losses in guided-wave propagation.
- Tailored gratings can couple radiation modes to enhance guided modes.
- Low-intensity nonlinear processes benefit from enhanced guided power.
Purpose of the Study:
- To analyze radiation mode contributions in a GaAs/AlGaAs nonlinear waveguide.
- To investigate a novel multiple grating design for enhanced second harmonic generation.
- To improve efficiency in low-intensity second harmonic (chi(2)) conversion processes.
Main Methods:
- Analysis of radiation modes in a chi(2) nonlinear waveguide.
- Design of multiple gratings at the core/substrate interface.
- Coupled mode equations for theoretical analysis.
- Numerical simulations to validate analytical results.
Main Results:
- Demonstrated enhancement of a fundamental guided mode at 1.55 microm.
- Achieved enhancement of a codirectional second harmonic guided mode at 0.775 microm.
- Observed efficient second harmonic field conversion through grating coupling.
Conclusions:
- Tailored gratings can effectively convert radiation modes into useful propagating modes.
- The proposed multiple grating design significantly enhances second harmonic conversion efficiency.
- This approach offers a viable solution for low-intensity nonlinear optical processes.
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