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<p>The original coherent lightwave systems were expected to offer significant performance gains relative to standard direct detection systems. This expectation has not been realized due to the effects of laser phase noise. The laser phase noise process results in the integration of a random variable that transitions over the integration period from a Gaussian distribution to a uniform distribution. The use of convolutional coding effectively replaces a single bit time, with its mostly noncoherently integrating latter portion, by several more coherently integrating bits. This primary bit-time effect comes in addition to the normal coding effect of efficiently trading bandwidth for error performance. The improvement in performance brought about from coding may enable coherent systems to live up to previous expectations. The contributions of this thesis include the visualization of the phase noise process, the efficient computation of the laser phase noise power factor probability density function, and the computation of performance curves for uncoded and coded systems. Additional sections on coherent lightwave systems and coding provide tutorial information. A potential military application is discussed, along with practical implementation issues.
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<br>Subjects: Optical communications; Laser phase noise; Coding</div>
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Neely, Thomas Elliott</div>
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