VCSEL-based smart pixels and their applications

Time division multiplexing has been generally used to increase the total throughput in optical communication systems. However, spatially-parallel optical interconnection technologies will be more effective over short distances (i.e., less than a few hundred meters). This is because data transmission in a parallel format makes system integration simple, reducing the latency of mux/demux functions, and thus results in lower power consumption and lower cost. VCSELs are very important for constructing parallel optical interconnection systems because they can emit a number of broadband optical signals simultaneously. In addition to their one- or two-dimensional structure, they have such advantages as a low cost, low operating current, and surface-normal emission. The surface-normal structure makes it easy to introduce optical input and output (I/O) into LSIs, which are important for constructing high-density optical interconnection systems.¹