ULTRAFAST TIME-DIVISION DEMULTIPLEXER BASED ON ELECTROOPTIC ON OFF GATES

Electrooptic on/off gate-based demultiplexers for high bit rate optical transmission systems are reported. Main advantages of using on/off gates for time-division demultiplexing are first, the on/off rate can be more than doubled without increasing the bandwidths of on/off gates or related electronics when the gates are cascaded, and second, their simple configuration is suitable for integration. The performance of electrooptic on/off gates as ultrafast time-division multiplexers is analyzed in terms of on/off rate, inter channel crosstalk, and demultiplexing loss, for the case when Mach-Zehnder (MZ) intensity modulators and electro-absorptive multi-quantum well intensity modulators are used. We demonstrate the electrooptic demultiplexing of a time-division multiplexed 49.6 Gb/s fixed pattern data stream using two cascaded Ti:LiNbO3 Mach-Zehnder intensity modulators both driven at 6.2 GHz, one eighth the incoming multiplexed data bit rate. We also achieve error-free 10 Gb/s demultiplexing to 5 Gb/s using cascaded Mach-Zehnder modulators both driven at 1.25 GHz. The power penalty due to the interchannel cross talk is 0.3 dB at the bit error rate of 10(-9), which agrees well with the calculated value.