A New Loopback Method of All-Optical Label Processing for Label Bit Scalability

We propose and demonstrate a new method to expand the label bit in an all-optical label processor with a multistage switching fabric. It utilizes a loopback configuration, where a probe pulse is fed back to the same switching fabric with wavelength conversion and the output probe pulse is discriminated by arrayed waveguide gratings. The feasibility of the loopback scheme was demonstrated for the two-bit pattern in the two-bit label using a single semiconductor optical amplifier-based Mach-Zehnder interferometer 1x2 all-optical switch. It is effective to reduce the number of switching elements and will expand the number of label bits.