Wideband Optical Multipath Interference Cancellation Based on a Dispersive Element

A novel scheme is proposed for analog multipath interference cancellation based on two polarization modulators (PolMs) and a dispersive element. Multiple optical compensation branches are formed by an array of tunable lasers. By adjusting the wavelength and the optical power of each tunable laser, the delay and the magnitude of the known interference signal can be finely tuned, so that the multipath interference can be accurately reconstructed for counter-phase cancellation. The dispersion-induced RF power fading in a dispersive optical link can also be compensated because of the PolM-based intensity modulation scheme, so the best cancellation depth can be obtained at any desired frequency. Experimental result shows that the proposed system can achieve more than 44-dB cancellation depth for wideband signals.