Fanout analysis of multi-stage optical clock distribution using optical amplifiers

An analytical model previously developed by the authors (1991) has been used to determine the timing skew in a multistage clock distribution network using optical amplifiers. The results show that a multistage distribution network using optical amplifiers can improve the total number of splittings by several orders of magnitude when compared to that obtained from a single-stage distribution network. The maximum allowable splitting for a given skew budget is shown to be very sensitive to the distribution skew introduced at each stage. It is also shown that the architecture and the parameters of the distribution network such as the gain of the optical amplifier, the rise time of the clock waveform, the optical filter bandwidth, and the extinction ratio can be optimized to obtain the maximum fanout allowed by the skew budget