A system includes, in part, a first optical modulator adapted to modulate a first optical signal with a first data to generate a first modulated optical signal, a second optical modulator adapted to modulate a second optical signal with a first clock signal to generate a second modulated optical signal, an optical multiplexer adapted to multiplex the first and second optical signals to generate a multiplexed optical signal, and an optical fiber adapted to carry the multiplexed optical signal. The second optical signal has a second wavelength that is different from the first wavelength.