Tapered polysilicon core fibers for nonlinear photonics

Area of Science:

• Materials Science
• Optical Engineering
• Nanotechnology

Background:

• Silicon photonics is crucial for advanced optical systems.
• Developing cost-effective and flexible silicon photonic devices remains a challenge.

Purpose of the Study:

• To demonstrate a novel method for creating ultra-small core polysilicon waveguides.
• To achieve the smallest optical cores in silicon fiber technology to date.
• To enable nonlinear transmission in polycrystalline silicon waveguides.

Main Methods:

• Fabrication of silicon fibers using a conventional drawing tower.
• Tapering the fibers to achieve core diameters of approximately 1 micrometer.
• Characterization of material properties and optical losses.

Main Results:

• Achieved the smallest optical cores (∼1 μm) for polysilicon waveguides.
• Demonstrated improved local crystallinity and significant reduction in material loss after tapering.
• Observed nonlinear transmission in the tapered polycrystalline silicon waveguides for the first time.

Conclusions:

• The developed fiber drawing and tapering method is highly scalable.
• This approach provides a route for low-cost, flexible nonlinear silicon photonic systems.
• The ultra-small core polysilicon waveguides show great promise for future photonic applications.