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Published on: August 5, 2013
Second-harmonic generation in Bragg-resonant quasi-phase-matched periodically segmented waveguides
Optics Letters
|October 28, 2009
Summary
Second-harmonic generation in waveguides shows significant efficiency despite a spectral valley. This is due to reduced reflections caused by random variations in domain boundaries.
Area of Science:
- Nonlinear optics
- Integrated photonics
- Materials science
Background:
- Second-harmonic generation (SHG) is a key nonlinear optical process.
- Quasi-phase-matching (QPM) in periodically segmented waveguides enables efficient SHG.
- Bragg-resonant cavities can enhance nonlinear interactions.
Purpose of the Study:
- To investigate SHG in Bragg-resonant quasi-phase-matched periodically segmented waveguides.
- To understand the impact of resonance on SHG efficiency.
- To identify mechanisms responsible for observed conversion efficiencies.
Main Methods:
- Experimental fabrication and characterization of periodically segmented waveguides.
- Theoretical modeling of light propagation and nonlinear interactions.
- Analysis of quasi-phase-matching curves and spectral responses.
Main Results:
- A deep spectral valley was observed in the QPM curve at resonance.
- Significant SHG conversion efficiency was achieved despite the spectral valley.
- Reduced reflections, particularly at the second harmonic (2ω), were identified as a contributing factor.
- Small random variations in domain boundary location and shape were proposed as the mechanism for reflection reduction.
Conclusions:
- Bragg resonance can be utilized for efficient SHG in periodically segmented waveguides.
- Random domain boundary variations can mitigate detrimental effects of spectral valleys.
- This work offers insights into optimizing nonlinear waveguide devices for enhanced performance.
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