System for optically splitting high-speed digital signals using cascading tree-type configuration wherein the number of successive level of cascading increase by a factor of two

An apparatus for testing high speed digital signals comprising:

• a) a signal generating means which transmits high-speed digital signals having a determined bitwidth;
• b) means for optically splitting said high-speed signals into a plurality of high-speed parallel data signals, said optical splitting means comprising optical demultiplexing means for splitting said high-speed signal into a plurality of high-speed parallel data signals, said optical demultiplexing means comprising a plurality of integrated optic directional coupling structures arranged to receive said high-speed signal and provide a plurality of parallel high-speed data signals, said plurality of integrated optic directional coupling structures being provided in a cascading tree-type configuration in which the plurality of integrated optic directional coupling structures in each successive level increases by a factor of 2;
• and
• c) means to convert said plurality of parallel high-speed data signals into a plurality of slow-speed data signals.