Digital Double-Sideband Frequency Translation for Transmission of RF MIMO Signals Over Fiber

In this letter, we demonstrate digitization, digital frequency translation, and predistortion compensation using an analog-to-digital converter (ADC) and digital-to-analog converter (DAC) for transmitting analog radio frequency (RF) multiple-input–multiple-output (MIMO) signals over a single fiber without wavelength-division multiplexing (WDM). This technique allows more flexible signal manipulation than the previous purely analog implementations. With the digital predistortion compensation for a Mach–Zehnder modulator (MZM), a 6-dB reduction in the intermodulation distortion is achieved for a 10-km RF over fiber link.