Reduction of Rayleigh Back-Scattering Noise Using RF Tone in RSOA Based Bidirectional Optical Link

The performance of bidirectional optical transmission system using the same wavelength can be degraded by Rayleigh backscattering signal. The backscattered signal makes phase noise and it is detected as intensity noise of baseband in photodiode. The unwanted noise interferes with the wanted data signals. The upstream baseband noise can be reduced by frequency chirp induced by RF tone combination in RSOA. We can get 1.5 dB power budget from this method through 1.25 Gbps, 20 Km bidirectional transmission using RSOA. Verification of the proposed technique has been performed through transmission experiment.