Operating conditions of OOK signal regenerator with feed-forward control

The optimum operating conditions for a signal regenerator employing a hybrid optical-electrical scheme for intensity-modulated signals are experimentally investigated. The scheme comprises an optical coupler, a photo-detector, and a Mach-Zehnder intensity modulator, and can suppress the intensity noise, accompanying extinction ratio degradation. It is shown that the operating conditions that achieve the lowest bit error rate (BER) after regeneration depend on the extinction ratio and the optical signal-to-noise ratio of the input signal. We also investigate the noise suppression effect under conditions that do not change the extinction ratio.