Simultaneous Multichannel Photonic Up-Conversion Based on Nonlinear Polarization Rotation of an SOA for Radio-Over-Fiber Systems

A photonic frequency up-conversion scheme based on the nonlinear polarization rotation (NPR) arising in a semiconductor optical amplifier for wavelength-division-multiplexing (WDM) baseband signals is proposed and experimentally demonstrated. Error-free simultaneous up-conversion of 4$\,\times\,$ 2.5 Gb/s WDM baseband channels with a 20-GHz local oscillator signal is experimentally demonstrated in the whole $C$-band. Compared with the cross-gain-modulation-based scheme, the proposed scheme is found to be almost independent of the wavelength separation between the probe and pump signals. Both the radio-frequency spectrum and the bit-error-ratio performance after electrical down-conversion have shown low distortion induced by the optical NPR-based up-conversion.