Fabrication and evaluation of sapphire fiber cladding via magnesium aluminate spinel sol-gel based approaches
Abstract
The absence of an effective and stable cladding has been a major hurdle in utilizing single crystal fibers for harsh environment sensing applications despite the promise of sapphire for temperatures as high as 1800°C. This work discusses the development of a high temperature cladding for sapphire fibers using wet chemical methods. Magnesium aluminate spinel has been chosen as the material for the cladding as it has a lower refractive index compared to sapphire and does not undergo significant interdiffusion with sapphire at temperatures below approximately 1200°C. Different sol-gel based approaches have been pursued to develop polycrystalline cladding layers with thicknesses greater than a micron, as required to ensure adequate confinement of the guided electromagnetic radiation within the fiber core. For sapphire fibers, high temperature stability of the cladded fibers as well as the effect of the cladding layer on optical characteristics under different application relevant gas environments at elevated temperatures has been investigated.
- Publication:
-
Fiber Optic Sensors and Applications XVI
- Pub Date:
- May 2019
- DOI:
- 10.1117/12.2518506
- Bibcode:
- 2019SPIE11000E..0JB