Calculations and Measurements of Raman Gain Coefficients of Different Fiber Types

Fiber Raman amplification using the transmission line is a promising technology to increase the repeater distance as well as the capacity of the communication systems. Because of the growing importance of fiber Raman amplification, it is desired to predict the magnitude and shape of the Raman gain spectrum from the doping level and refractive index profiles of different fiber designs. This thesis develops a method to predict the Raman gain coefficients and spectra for a pure silica core fiber and two different types of GeO2-doped silica fibers given their index profiles. An essential feature of the model is the inclusion of the variation in Raman gain coefficient over the mode field due to the variation in the Ge concentration across the fiber core. The calculated Raman gain coefficients were compared with measurements of the peak Raman gain on a step-index GeO2-doped fiber and with published measurements from various sources. Agreement between the calculated and measured peak gain for the step-index fiber was excellent. There was qualitative agreement with published measurements but there were significant differences between the calculated and published gain coefficients, which are not understood. Part of the work sought a way of predicting Raman gain coefficients from a standard gain curve given only the fiber type and the effective area. This approach appears promising for moderately-doped fibers with the proper choice of effective area.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Electrical and Computer Engineering

Department dc:contributor.department

Electrical and Computer Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2002

Author dc:creator

• Kang, Yuhong

Chair dc:contributor.committeechair

• Stolen, Roger Hall

Committee members dc:contributor.committeemember

• Jacobs, Ira
• Safaai-Jazi, Ahmad

• effective Raman gain and Raman gain coefficient
• stimulated Raman scattering
• GeO2 concentration
• Fiber Raman amplifier

Statement dc:rights

• In Copyright

Licence dc:rights.uri

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

Dc Identifier Other

etd-01102003-020757

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/30878