Rb/Ba side-diffused ridge waveguides in KTP.

Area of Science:

• Materials Science
• Optoelectronics
• Nonlinear Optics

Background:

• Potassium Titanyl Phosphate (KTP) is a crucial material for nonlinear optical (NLO) applications.
• Fabrication of high-quality waveguides is essential for efficient NLO devices.
• Understanding waveguide properties like attenuation and conversion efficiency is key for device performance.

Purpose of the Study:

• To characterize ridge waveguides fabricated in KTP using specific fabrication techniques.
• To evaluate the optical properties, including attenuation and second-harmonic generation (SHG) efficiency, of these KTP waveguides.
• To investigate the impact of substrate orientation on waveguide stability and performance.

Main Methods:

• Fabrication of ridge waveguides in KTP substrates using diamond-blade dicing.
• Rb/Ba ion exchange process for waveguide formation.
• Optical characterization including attenuation measurements at 1060 nm and SHG efficiency measurements at 1064 nm.

Main Results:

• Low attenuation coefficients of 0.3 dB/cm for TM and 0.4 dB/cm for TE polarization were measured.
• High internal conversion efficiency of up to 3.3%/(W cm²) for type-II SHG was achieved.
• Waveguide fabrication with z-axis in the surface plane perpendicular to the waveguide direction improved thermal stability by hindering ion diffusion.

Conclusions:

• The developed fabrication method yields high-performance KTP ridge waveguides suitable for NLO applications.
• The achieved low attenuation and high SHG efficiency demonstrate the potential of these waveguides for integrated optics.
• The specific substrate orientation offers enhanced thermal resistance, crucial for device longevity and operation.