All-optical packet switching with all-optical header processing using fabry-perot laser diode

Abstract

In this work, we present recent results in all-optical packet switching, in which both header processing and packet routing are carried out in optical domain using multi-wavelength injection locking of a Fabry-Perot laser diode. First, by using a novel self-routing address format for the data packets and a special two-intensity level control signal, we demonstrated all-optical header processing and packet control signal generation with a single Fabry Perot laser diode (FP-LD). In the self-routing address scheme, each output port of all the nodes in a network is associated with a bit in the header address. Using this routing scheme, the header processing unit in a node of a network is only required to process the header bits of the incoming data packet that are associated with its output port. The special two-intensity level control signal can be generated by using two Mach-Zehnder intensity modulators and two pulse pattern generators. We also found that the relaxation oscillation of a directly current modulated DFB laser diode can be used as the special control signal. We then demonstrated that a single Fabry-Perot laser diode can simultaneously serve as an all-optical on-off switch and as all-optical header processor. The demonstrated header rate is 5 Gb/s and the payload rate is 10 Gb/s. However, because of the format of the address and the finite response time of the Fabry-Perot laser diode, part of the header bits of the "unwanted" data packets are able to pass through the FP-LD, thus limiting the cascadability of the switch. In order to eliminate the residual header bits problem when a single FP-LD is used, we used a two-stage implementation which uses a FP-LD as the header processor only and execute the packet switching at a separate stage. We also demonstrated an all-optical add-drop node which can be used to construct an all-optical packet switched networks. Finally, we successfully demonstrated all-optical packet switching using optical 2R regeneration after the optical signal is transmitted through 100 km of optical fiber.