الفهرس 
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Abstract
The main objective of this thesis is to investigate the use of Orthogonal
Frequency Division Multiplexing (OFDM) in optical communication systems. We
study optical OFDM using both intensity modulation and linear field modulation.
In optical OFDM using intensity modulation, our work and contribution focus
on DC-biased optical OFDM (DCO-OFDM). Asymmetrical clipping optical OFDM
(ACO-OFDM) is also described. We mathematically analyze a DCO-OFDM system
with the focus on the effect of the nonlinear clipping noise on the bit-error rate (BER)
performance. Specifically, the clipping noise statistics are studied in details, and an
analytical formula for the BER is derived. In addition, an expression for the optimal
value of the DC bias is derived and is shown to closely agree with the simulation
results.
In optical OFDM using linear field modulation, we study the effect of the DC
bias point and the modulation index of Mach-Zehnder modulator on the BER
performance of coherent optical OFDM. Our simulations confirm that the optimal
bias point for coherent optical OFDM systems is the quadrature point. In addition, the
optimal value of the modulation index for the chosen set of parameters is found to be
approximately -5 dB.