Highly efficient, modal phase-matched second harmonic generation in a double-layered thin film lithium niobate...

Area of Science:

• Nonlinear optics
• Integrated photonics
• Materials science

Background:

• Second harmonic generation (SHG) is crucial for frequency conversion in photonics.
• Lithium niobate (LiNbO3) is a key material for nonlinear optical devices.
• Integrated photonic platforms offer miniaturization and scalability.

Purpose of the Study:

• To numerically investigate SHG in double-layered lithium niobate on insulator (LNOI) ridge waveguides.
• To explore modal phase matching (MPM) as a technique for efficient SHG.
• To analyze the impact of geometric dimensions and thermal tuning on SHG performance.

Main Methods:

• Numerical investigation of modal dispersion in LNOI ridge waveguides at the C-band.
• Calculation and analysis of modal phase matching by varying waveguide geometric dimensions.
• Simulation of phase-matching wavelength and conversion efficiency dependence on geometry.
• Analysis of the thermal-tuning capability of the MPM scheme.

Main Results:

• Modal dispersion in LNOI ridge waveguides was numerically calculated and analyzed.
• Modal phase matching was achieved by tuning the waveguide's geometric dimensions.
• Phase-matching wavelength and conversion efficiency were investigated as functions of geometric parameters.
• The thermal-tuning ability of the MPM scheme was successfully analyzed.

Conclusions:

• Highly efficient second harmonic generation is achievable in double-layered LNOI ridge waveguides.
• Modal phase matching provides an effective route for optimizing SHG in these devices.
• The geometric tunability and thermal properties of the MPM scheme are promising for practical applications.