Monolithically integrated multi-wavelength filter and second harmonic generator in aperiodically poled lithium...

Area of Science:

• Nonlinear optics
• Materials science
• Integrated photonics

Background:

• Lithium niobate is a key material for nonlinear optical devices.
• Integrated photonic devices require efficient and multifunctional components.
• Aperiodic poling offers advanced control over nonlinear optical processes.

Purpose of the Study:

• To design and characterize aperiodically poled lithium niobate (APLN) for integrated dual nonlinear-optical devices.
• To enable simultaneous operation as electro-optically active (EOA) filters and frequency doublers.
• To compare the performance of single-structure vs. cascade APLN designs.

Main Methods:

• Simulated annealing was used to design aperiodic domain structures in LiNbO(3).
• Experimental characterization of fabricated APLN devices was performed.
• Performance metrics including second-harmonic-generation efficiency and filter bandwidth were measured.

Main Results:

• A single APLN device design achieved a 2.44-fold enhancement in second-harmonic-generation conversion efficiency.
• The single APLN device demonstrated a 2.4-time reduction in filter transmission bandwidth compared to cascade designs.
• Both designs functioned as 4-channel EOA filters and 4-channel frequency doublers in the telecom band.

Conclusions:

• Single-structure APLN devices offer superior performance for integrated dual nonlinear-optical functions.
• APLN is a promising material for advanced integrated photonic applications.
• Optimized aperiodic domain engineering provides enhanced device efficiency and selectivity.