Abstract: An all-optical linear feedback circuit for use, for example, as a maximal length pseudo random bit sequence generator includes an all-optical logic circuit that is capable of generating 2N?1 bit maximal length pseudo random bit sequences on an optical channel at high data rates e.g. 80 Gbit/s. In the pseudo random bit sequence generator of the present invention, intensity-dependent phase modulation of at least one included semiconductor optical amplifier (SOA) is implemented. The maximum data rate is limited by the fast gain recovery time of the carriers in the SOA. An optical logic gate of the pseudo random bit sequence generator of the present invention may be constructed using various nonlinear elements that provide ultra-fast intensity-dependent phase modulation.