Abstract: An add-drop network element (100) for an optical communications network. The add-drop network element comprises an optical amplifier (102) having an input port and an output port. The add-drop network element comprises also comprises an optical coupler (104) and an optical splitter (106). The optical coupler (104) comprises an add input port, a through input port and an output port, the output port of the optical coupler (104) being connected to the input port of the optical amplifier. The optical splitter (106) comprising a drop output port, a through output port and an input port, the input port of the optical splitter (106) being connected to the output port of the optical amplifier.

Abstract: In an optical data transmission system, high frequency pulsed optical signals are transmitted along an optical fiber. These pulses are attenuated and distorted by transmission over long optical fibers making detection of data difficult at the receiving end. The allowable pulse profile is determined by an eye diagram which is non-symmetrical with respect to logic 1 and 0 levels. By positioning the eye diagram closer to the logic 0 level, detection in the presence of noise introduced during transmission of the optical pulses, can be significantly improved.