A circuit model BOSS simulation of nonlinear effects in long distance fiber optic systems

The combined effect of group velocity dispersion (GVD) and nonlinearity limits the transmission distance of fiber optic communication systems. By designing a circuit that can model this effect and simulating it using the Block Oriented Systems Simulator (BOSS), we can study the pulse distortion and broadening that may occur. The nonlinearity considered here is self-phase modulation (SPM). A loop system is designed where each pass of the system corresponds to 200 km of fiber. The system mainly consists of a Butterworth bandpass filter which models the dispersion in the fiber and a VCO that imposes a phase modulation on the input signal thus modeling the intensity dependent phase shift due to SPM. By changing various parameters of the circuit, the dispersion limited distance, the nonlinearity limited distance and other related factors can be altered. With D=-0.04 ps/km.nm, the effect of changing the nonlinear limited distance and thus the nonlinear effect is studied and simulated. The results are compared with a simple theoretical model for pulse broadening that has appeared in the literature. Although the simulation results exhibit the same qualitative behavior as the theory, there are significant quantitative differences. The reason for these differences are discussed.

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

1993

Author dc:creator

• Mehta, Shilpa D.

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-07112009-040230

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/43655