Demonstration of Free-Space 300-Gbit/s QPSK Communications Using Both Wavelength- and Mode-Division-Multiplexing in the Mid-IR

We demonstrate free-space wavelength- and mode-division-multiplexed communications in the mid-infrared wavelength region. A total capacity of 300 Gbit/s is achieved using three wavelengths and two orbital angular momentum modes each carrying a 50-Gbit/s QPSK signal.