Photoinduced Fresnel reflectors in germanium-doped optical fibers

A novel method of fabricating low reflectance mirrors has been developed based on the photosensitivity of hydrogen-loaded, germanium-doped optical fibers. Using a side-writing technique, point-wise refractive index changes have been induced in the core of Ge-doped optical fibers via ultraviolet light from a high power excimer laser. These refractive index changes cause Fresnel reflections at the boundary of the higher photoinduced index change and the lower index in the unexposed core. The boundary of the two refractive indices may be considered a low reflectance mirror. Several techniques have been explored to characterize the Fresnel reflectors including optical time domain reflectometry (OTDR) and spectral analysis. In-line, optical fiber Fresnel reflectors have applications as internal mirrors in intrinsic Fabry-Perot interferometric (IFPI) sensors and OTDR distributed strain sensors. Photoinduced IFPI sensors have performed well as temperature sensors, strain sensors, and vibration sensors. Improved manufacturing techniques are also discussed for future developments. The photoinduced IFPI sensor is inexpensive to manufacture and involves little skill, in contrast to the labor-intensive fabrication techniques of conventional IFPI sensors. The IFPI sensor has commercial applications in embedded structures, high temperature environments, and situations with large EMI conditions.

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

1994

Author dc:creator

• Plante, Angela J.

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-06162009-063318

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/43334