An optical communication system is provided comprising of a three terminal silicon based light emitting device operating by means of avalanche carrier multiplication and emitting at the below threshold wavelength detection range for Silicon of 850 nm; a low loss optical waveguide operating in the below threshold wavelength detection range for Silicon of 850 nm; and an optical detector, wherein a complete and all-silicon optical communication system is formed being capable of transferring electrical signals in terms of optical intensity variations, such intensities then being propagated through the waveguide and being detected by the optical detector; and being converted back to electrical signals. In a particular mode of operation of the system, wavelength modulation may be obtained. In other applications, transponding action and optical amplification may be obtained.