Abstract
The next generation of transoceanic submarine cable systems will use in-line fiber
amplifiers to replace electrical regenerators. This new approach requires a better
understanding of the fiber waveguide, especially the nonlinear characteristics. It has been
demonstrated, both by numerical simulation and experiments, that the Kerr effect has the
most significant degradation effects on these systems with a single or a few channels. In
this dissertation, the numerical simulation is the principal approach but this is
supplemented with some analytical studies.
There are two phenomena that are directly associated with the Kerr effect: spectrum
broadening and four wave mixing (FWM). The broadened signal spectrum enhances the
dispersion effect and consequently increases the inter symbol interference. This distortion is
significant when the dispersion is relatively large. U sing erbium doped fiber amplifiers,
amplified spontaneous emission (ASE) noise is added to the signal The FWM effect
between the noise and signal causes a loss in the signal power. In the close vicinity of the
zero dispersion wavelength, the FWM effect is maximized due to the loose phase match
condition.
In order to reduce these degradation effects, dispersion compensation has recently
been proposed. Using this approach, it is possible to optimize the system configuration to
achieve the best performance. In this dissertation, the dispersion compensation distance,
dispersion coefficient, channel bandwidth, bit rate and the degree of imperfect
compensation are all subject to the optimization. The evaluation is obtained by the
numerical simulation using the mean squared error (MSE), which can be derived as the
difference between the wavefronts received by a back-to-back receiver and a receiver at
the end of the channel. Although the MSE can't be related to the bit error directly, this
research provides the insight into how dispersion and noise behave in the presence of the
Kerr effect and points the direction for future experimental research. ?
|
next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.
![[VT]](http://scholar.lib.vt.edu/images/ETD-db/restricted.gif)
