A 1024-channel fast tunable delay line for ultrafast all-optical TDM networks

Based on a passive k-stage feed-forward delay line structure, this letter presents a novel scheme which allows fast tuning among as many as 2 ^k ×2 ^k ultrafast time-division multiplexed (TDM) channels in all-optical networks. At a lower speed, a simple selection rule is applied at the input and output of the structure to set the state of the delay. In the experimental demonstration, the delay line can be tuned to any of the 1024 50-Mb/s channels in a 50-Gb/s all-optical TDM network with a five-stage structure and two E/O modulators. The average reconfiguration time is about 20 ns.