Fast synchronous switching in an optical time-multiplexed space switch (OPTIMUSS)

The authors have demonstrated the principle of a fast optical time-space-time switch capable of expansion to capacities in the order of terabits per second. The (sparsely populated) 16×16, strictly nonblocking switch breaks into an SDH bit stream and operate synchronously with it. The overall switch structure is polarisation independent but incorporates polarisation scrambling techniques in conjunction with polarisation sensitive 1:16 hybrid Mach-Zehnder switches. These lithium niobate components have been realised with fibre to fibre losses as low as 7.5 dB and extinction ratios of better than 25 dB. Polarisation sensitivity is traded, in the active part of the switch, for a low switching voltage of less than 6 V. Together with hybrid packaging of synchronisation and drive electronics, this enables transition times of under 5 ns to be achieved. The switch is capable of routing STM or ATM packets as short as 12.9 ns without significant degradation, regardless of the bit rate or number of wavelengths channels (within a 50 nm window) carried