Efficient second-harmonic generation through cascaded optically poled fibers

Area of Science:

• Nonlinear Optics
• Fiber Optics
• Photonics

Background:

• Second-harmonic generation (SHG) is crucial for frequency conversion.
• Optically poled fibers offer a promising nonlinear medium.
• Improving SHG efficiency in practical devices remains a challenge.

Purpose of the Study:

• To experimentally demonstrate efficient second-harmonic generation (SHG) using spliced optically poled fiber segments.
• To investigate the impact of segment splicing on overall conversion efficiency.
• To compare the performance of a multi-segment device against a single poled fiber.

Main Methods:

• Fabrication of optically poled fiber segments.
• Splicing of multiple (five) 20 cm long poled fiber segments.
• Experimental measurement of second-harmonic generation conversion efficiency at various fundamental power levels.

Main Results:

• A five-segment spliced fiber device achieved a 5.5-fold increase in conversion efficiency compared to a single segment.
• Maximum conversion efficiency reached 5.4% at a fundamental average power of 4.2 mW.
• The multi-segment device consistently outperformed a single fiber of equivalent total length.

Conclusions:

• Splicing optically poled fiber segments is an effective method for enhancing second-harmonic generation efficiency.
• This segmented approach offers a scalable solution for efficient frequency conversion in fiber-based devices.
• The demonstrated technique provides a practical pathway towards higher-performance photonic devices.