Modulation and multiplexing in optical communication systems
01 January 2009
The success of digital information processing over the last century has triggered the demand to transport massive amounts of digital information, ranging from on-chip data buses all the way to inter-planetary distances. Optical communication systems have been replacing electronic and RF techniques starting at the most demanding capacity-constrained and sensitivity-constrained applications and are steadily progressing towards more implementation-constrained shorter-reach systems that require dense integration, low power consumption, and low cost. Modulation and multiplexing techniques are key design elements of sensitivity-constrained and capacity-constrained systems, used to harvest the bandwidth advantages that optical technologies fundamentally offer. Spectrally efficient modulation will stay a key area of research for capacityconstrained systems. As WDM capacities over conventional fibers are approaching their fundamental limits, breakthroughs in fiber design and in complementary multiplexing techniques are expected to further scale capacity.
