The direct modulation of diode laser output for optical data transmission is the oldest encoding technique and the simplest but is plagued by problems (delay time and relaxation oscillations) which limit its usefulnes...
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The direct modulation of diode laser output for optical data transmission is the oldest encoding technique and the simplest but is plagued by problems (delay time and relaxation oscillations) which limit its usefulness to a small number of niche applications. Using a phase space representation of the transient, it is shown that a simple modification of the shape OF the injected current's switch may dramatically improve the performance of this old technique, both for the switch-up as well as for the switch-down of the laser. Below- and above-threshold biasing schemes are considered and a physical discussion of the realisability of the technique is offered.
We propose a systematic trellis encoding technique based on trellis partitioning and on newly defined branch distances. This encoding technique avoids the usual exhaustive search for finding good trellis codes. It giv...
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We propose a systematic trellis encoding technique based on trellis partitioning and on newly defined branch distances. This encoding technique avoids the usual exhaustive search for finding good trellis codes. It gives the lower and upper bounds on free distance which depend only on the encoder memory and the signal space. We also discuss the optimal combination of signal set and trellis and give the sufficient condition for avoiding catastrophic codes.
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