Chalcogenide Glass Hollow-Core Microstructured Optical Fibers

Chalcogenide Glass Hollow-Core Microstructured Optical Fibers

Citation

Shiryaev VS (2015) Chalcogenide glass hollow-core microstructured optical fibers. Front. Mater. 2:24. doi: 10.3389/fmats.2015.00024 

Keywords

  • chalcogenide glass
  • hollow-core microstructured optical fibers (HC-MOFs)
  • mid-infrared (IR)
  • optical losses
  • negative curvature
  • photonic crystal fibers (PCFs)
  • fabrication
  • transmission 

Brief

This article reviews the recent developments, manufacturing techniques, and challenges of chalcogenide glass hollow-core microstructured optical fibers for mid-infrared applications. 

Summary

This article provides an overview of recent developments in chalcogenide glass hollow-core microstructured optical fibers (HC-MOFs) for mid-infrared applications.

The sources highlight the advantages of HC-MOFs, including:

  • Low theoretical losses: The sources explain that HC-MOFs offer the potential for very low transmission losses because light travels through air, where material absorption and Rayleigh scattering are minimal compared to glass.
  • Broad transmission range: HC-MOFs can transmit light over a wider range of wavelengths compared to traditional step-index fibers.
  • Strong light-gas interaction: The presence of gas in the hollow core enables strong interaction between light and gas, which is beneficial for applications like Raman amplification.

The sources emphasize that chalcogenide glasses are particularly well-suited for mid-infrared HC-MOFs due to their unique properties. These include:

  • Wide transmittance range: Chalcogenide glasses can transmit light in the 1–12 µm range.
  • Low intrinsic losses: They have naturally low losses in the mid-IR region.
  • High refractive index: The high refractive index of chalcogenide glasses (2.4–3.0) makes them suitable for compact nonlinear devices.
  • High nonlinear refractive index: Their nonlinear refractive index (n2) is significantly higher than silica glass, making them ideal for fiber-based photonic devices.

However, the sources acknowledge several technical challenges in fabricating chalcogenide HC-MOFs, including:

  • Optimizing design and geometry: Researchers are actively working on determining the ideal structural parameters of these fibers.
  • Improving glass purity: Achieving high chemical and phase purity in the chalcogenide glass is crucial for minimizing losses.
  • Enhancing drawing techniques: Refining fiber drawing techniques is essential to prevent deformation of the delicate photonic crystal structure.

The sources describe the "stack and draw" technique as the primary method for creating chalcogenide HC-MOF preforms, which involves assembling capillaries within a substrate tube. The sources also mention the challenges associated with the adhesion of chalcogenide glasses to silica glass during preform fabrication. They point out that adhesion is strongest near the glass transition temperature of chalcogenide glasses and can lead to preform cracking during cooling.

Despite these challenges, researchers have successfully fabricated chalcogenide HC-MOFs capable of transmitting mid-infrared radiation, including CO2 laser light. However, the optical losses in these fibers are currently higher than theoretical predictions. To achieve losses closer to theoretical limits, further research is needed to optimize fiber design, drawing conditions, and glass purity. The sources also stress the importance of addressing the optical aging of chalcogenide HC-MOFs caused by exposure to atmospheric moisture. This aging process leads to increased optical losses due to the formation of hydroxyl groups and water molecules within the fiber's air holes. To mitigate this, researchers are exploring methods to protect the fibers from moisture, such as using polymer coatings. 

Origin: https://www.semanticscholar.org/paper/Chalcogenide-Glass-Hollow-Core-Microstructured-Shiryaev/b3b3c4bffdbeca46fba87269bbecfd339f228d51
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