Advanced modulation formats for short reach optical communication systems

The use of advanced modulation formats helps to reduce the number of components required for short reach optical communication modules at 100 Gb/s and beyond. Unlike long haul optical communication systems where externally modulated high order modulation formats with coherent detection receivers are used, direct modulated lasers with direct detection are likely to be employed for short reach system implementation. Here we discuss the performance of pulse amplitude modulation, carrierless amplitude/phase modulation, and direct detection orthogonal frequency- division multiplexing for short reach optical communication systems. Their possible use for future high-capacity short reach optical communication systems is explored.