Latency reduction in optical interconnects using short optical pulses

We present a new method of latency reduction in optical interconnects: using very low duty cycle return-to-zero encoding (i.e., subpicosecond pulses). An analytical comparison of three different receiver architectures, including transimpedance, integrating, and totem-pole diode pair, is presented. For all three receivers, we demonstrate that using short pulses instead of nonreturn-to-zero (NRZ) shortens the circuit delay. We also experimentally demonstrate a ∼65% reduction in latency of a transimpedance receiver by using short optical pulses. Finally, we show that the latency of optical interconnects can be comparable to or even less than electrical interconnects for global on-chip communication.