The design of an electro-optic control circuit for photonic packet switching applications

We demonstrate the design and experimental implementation of an electro-optic control system that is used to detect the arrival of packets at the optical switch input, process the headers of the packets, and control switching according to the header content for both fixed and variable length packets. We also demonstrate the flexibility of the electro-optic crosspoint switch for implementation in a photonic packet switching (PPS) network. Furthermore, contention resolution is demonstrated in the electro-optic crosspoint switch by detecting packets at the input ports and controlling the switch operation accordingly. By incorporating this control system into the crosspoint switch it is possible to route contending packets to a re-circulating fiber delay line and control the switch output in a flexible manner for any type of traffic depending on the applied switching algorithm. The experiments are carried out with 155 Mbit/s headers and 10 Gbit/s payloads transmitted on a single wavelength with a guard time of 12.8 ns between header and payload. PPS with bit error rate (BER) less than 10^-9 is demonstrated. Error free contention resolution is shown with the main signal degradation being from the switch cell attenuation and amplifier ASE that can be alleviated by eliminating fiber-to-fiber transmission loss in the crosspoint.