Abstract: A receiver at a node in an optical network receives an optical clock signal and an OTDM datastream. A detector converts the clock signal to the electrical domain. A variable delay stage applies a selected delay to the clock signal in the electrical domain. A non-linear electro-optic modulator which may be an electro-absorption modulator, receives the OTDM datastream at its optical input. An electrical control input of the modulator is connected to the output of the variable delay stage. The electro-optic modulator outputs an OTDM channel selected by setting the delay of the variable delay stage. The variable delay stage may include a number of logic gates, particularly AND gates, connected between a pair of microstrip delay lines. The gates are controlled to provide different paths with different corresponding delay times for the clock signal.