Sapphire fiber in optical sensors

The physical and optical properties of sapphire fiber has been investigated in an effort to create a high temperature optical fiber sensor. Sapphire fiber demonstrates high optical attenuation. This attenuation is very sensitive to injection conditions, and roughly proportional to the cube of the fiber length. The loss was found to be largely due to surface scattering, which causes the fiber to deviate from a perfect cylindrical waveguide. Because of the high optical losses (and high cost) of sapphire fiber, it is desirable to fashion a splice between the sapphire and an inexpensive, low-loss silica fiber so that sapphire is only used in the sensor head. The great physical disparities between sapphire and silica make this a challenging proposition. One solution demonstrated here is the sapphire capillary tube splice, in which the two fibers are aligned in a sapphire capillary tube and bound together with alumino-silicate glass. Sapphire fiber optical sensors cannot use standard interferometric techniques used with silica fibers because sapphire fibers are not clad, making a strongly guiding, highly multimode waveguide that introduces a great deal of modal distortion to interferometric signals. Consequently a simple intensity-based sensor was developed and tested using sapphire. More exotic intensity-based sensors are explored with their applicability to a sapphire fiber sensor head.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Electrical Engineering

Department dc:contributor.department

Electrical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1995

Author dc:creator

• Barnes, Adam

Chair dc:contributor.committeechair

• Claus, Richard O.

Committee members dc:contributor.committeemember

• Murphy, Kent A.
• Wang, Anbo

• high temperature sensors
• optical fibers

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-09052009-041053

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/44617