All-Optical Decrementing of a Packet Time-to-Live (TTL) Field and Subsequent Dropping of a Zero-TTL Packet

We demonstrate an optical time-to-live (TTL) decrementing module for optical packet-switched networks. Our module acts on a standard NRZ-modulated binary TTL field within a 10 Gb/s packet and decrements it by one if the TTL is nonzero. If the TTL of the incoming packet is zero, the module signals an optical switch to drop the packet. Our technique is independent of the TTL length, does not require the use of ultrashort RZ optical pulses, requires no guard time between the end of the TTL field and the packet data, and has only a 2.4 dB power penalty at 10^-9 bit-error rate.