Grating-enhanced second-harmonic generation in polymer waveguides: role of losses

Area of Science:

• Nonlinear optics
• Waveguide optics
• Materials science

Background:

• Second-harmonic (SH) generation is a key nonlinear optical process.
• Polymer waveguides offer potential for integrated photonic devices.
• Understanding loss effects is crucial for optimizing SH generation efficiency.

Purpose of the Study:

• To numerically investigate second-harmonic generation in corrugated polymer waveguides.
• To elucidate the impact of waveguide losses on SH generation efficiency.
• To explain the observed angular dependencies and discuss phase matching.

Main Methods:

• Rigorous electromagnetic theory for numerical simulation.
• Comparison of theoretical predictions with experimental data.
• Phenomenological analysis of angular dependencies.

Main Results:

• Small losses minimally affect nonresonant SH generation but reduce resonant enhancement.
• High losses can lead to dips in SH efficiency near guided-wave excitation.
• Angular dependencies are explained, highlighting the role of phase matching.

Conclusions:

• Waveguide losses play a critical role in determining SH generation efficiency.
• The study provides insights into optimizing SH generation in polymer waveguides.
• Understanding loss mechanisms is essential for practical device applications.