An optical signal switching network having a transmitter and a receiver, wherein the transmitter includes a data generator for generating a data signal and a clock signal having the same frequency as the data signal; a clock attenuator for attenuating a frequency of clock signal generated in the data generator at a predetermined ratio; a signal synthesizer for synthesizing the data signal and the attenuated clock signal; a laser generator for generating a laser beam used to transmit the synthesized data signal and clock signal; and a modulator for coupling the synthesized data signal and clock signal to the laser beam and modulating the coupled signal, thereby providing the modulated optical signal to be transmitted to the receiver over an optical fiber