Title page for ETD etd-04082009-040801
|Type of Document
||Kelkar, Anish S
||Dynamic range of analog fiber optic links used in microcellular mobile radio applications
||Master of Science
|Reed, Jeffrey Hugh
|Woerner, Brian D.
|Date of Defense
The use of analog fiber optic links for microcellular mobile radio comminications has been
the focus of considerable research recently. These systems have the advantages relative to
coaxial cable of low noise and enormous bandwidth. Analog subcarrier multiplexing
techniques are used for transmitting the mobile signals over the fiber. Use of this
technology however presents some unique problems due to the nonlinearities of the fiber
optics system and the noise introduced by it. In this thesis, we analyse the dynamic range
of the fiber links used for these applications.
The dynamic range is limited by the noise and the nonlinear distortion introduced by the
fiber link. The main sources of nonlinear distortion are threshold clipping, gain saturation
of the laser, and the combination of laser chirp and fiber dispersion. We have analytically
modeled these nonlinearities and used these models to understand the dependence of the
nonlinear distortion on the physical parameters of the laser diode and the fiber and also on
the modulation index per channel and the number of channels. The performance of the 1S-
19 AMPS signals and the IS-54IDMA signals in the presence of fiber link noise is also
discussed. Finally, the dynamic range of the fiber link for both AMPS and IDMA signals
has been analyzed. The dynamic range of the fiber link is limited by the threshold clipping
nonlinearity. It is also highly dependent on the number of mobile signals that are being
communicated over the fiber link.
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