Reducing fiber scattering loss through hot-diffusion: a study on eliminating core-cladding interface defects

Area of Science:

• Materials Science
• Optical Engineering
• Photonics

Background:

• Chalcogenide fibers exhibit optical losses significantly exceeding theoretical predictions.
• Rough core-cladding interfaces causing optical scattering are a primary contributor to high fiber loss.

Purpose of the Study:

• To investigate the effectiveness of the extrusion-assisted hot-diffusion method in reducing optical scattering loss in chalcogenide fibers.
• To characterize the core-cladding interface and diffusion process to understand loss reduction mechanisms.

Main Methods:

• Fabrication of optical fiber preforms using the extrusion-assisted hot-diffusion method.
• Characterization of core-cladding interface quality and diffusion using scanning electron microscope-energy-dispersive x-ray spectroscopy (SEM-EDS) and Raman spectroscopy.
• Modeling of defect and diffusion layers to analyze the impact on light scattering loss.

Main Results:

• Achieved a diffusion depth of 40.5 μm under hot-pressing conditions at 320°C.
• Demonstrated a 58% reduction in average fiber loss, from 4.5 to 1.88 dB/m in the 5-6 μm range.
• Observed a minimum fiber loss of 0.68 dB/m at 2.64 μm.

Conclusions:

• The hot-diffusion treatment effectively reduces optical scattering loss by improving the core-cladding interface quality.
• This method significantly enhances the performance of chalcogenide fibers for optical applications.