Optics in computers, servers and data centers

Based on well-known laws of physics, a lower bound on the energy-per-bit required for transmitting information using a photonic channel is established. The analysis includes the energy required to convert information from the electronic to the photonic domain and back. We investigate links that employ a directly modulated laser as well as links that employ an external modulator. It is shown that the power dissipation of the channel also imposes a bound on the maximum bandwidth density for a photonic link. Keeping this in mind, opportunities for optics in computing systems are discussed, especially from a systems perspective. © 2012 SPIE.