Postcompensation for nonlinearity of Mach-Zehnder modulator in radio-over-fiber system based on second-order optical sideband processing

摘要

A postcompensation technique for nonlinearity of a Mach-Zehnder modulator in a radio-over-fiber (ROF) system is proposed and experimentally demonstrated based on second-order optical sideband processing and optical carrier band attenuation. The phase of the second-order optical sideband is shifted to suppress the third-order intermodulation distortion (IMD3) in a direct detection ROF link. The optical carrier band is attenuated to make two kinds of origins of IMD3 have equal intensity and cancel each other out. A spurious-free dynamic range of 124.8 dB centre dot Hz~(2/3) is achieved, which is about 25 dB more than that without compensation.