All-optical bit-error monitoring system using cascaded inverted wavelength converter and optical NOR gate

A novel all-optical bit-error monitoring system is demonstrated by cascading two all-optical logic gates: an inverted wavelength converter and an optical NOR gate which are realized using injection-locked laser diodes operating at different thresholds. Real-time optical monitoring signal is generated which indicates the positions and duration of both bit and burst errors in 10-Gb/s nonreturn-to-zero signals.