40-Gb/s Optical Packet Buffer Using Conversion/Dispersion-Based Delays

We experimentally demonstrate a continuously tunable, all-optical packet buffer based on conversion dispersion delays. 40-Gb/s asynchronous transfer mode (ATM) packets with return-to-zero on-off keying data are buffered up to ten-packet length (116 ns). The packet buffer performance is characterized for several delay values. Power penalties of 3, 2, and 0.5 dB for zero-packet, five-packet, and ten-packet delays are achieved, respectively, at a bit error rate (BER) of 10^-9. Reconfiguration of the packet buffer is also investigated and reconfiguration times as fast as 25 ps are shown by using a high-speed optical switch to toggle between wavelength conversion pumps. The reconfiguration is also demonstrated for a 1 ns guard time between the packets. It is observed that reconfiguration with this method results in ~1.1 and ~2 dB extra power penalty at 10^-9 BER for 1 and 25 ps guard times, respectively.