16-Wavelength DWDM A-RoF with Stimulated Brillouin Scattering Suppression, for Antenna Remoting in Wireless Front-haul

A DWDM analog radio over fiber (ARoF) system connected a base band unit (BBU) to a radio remote unit (RRU). It is capable of carrying massive-MIMO, sub-6GHz and mmWave signals. It was tested using live mmWave traffic. Uplink and downlink each comprised 16 wavelengths, with directly-modulated lasers. Each wavelength capable of carrying a 2 GHz RF-bandwidth signal on a 1.5 GHz IF carrier, at RF ACLR of 40 dBc at 12 km fiber, including 3 dB ACLR improvement by offsetting the wavelength from the optical mux grid by 22 GHz. Using ARoF, no DSP is needed at the RRU. This reduces weight and power consumption on the tower compared to eCPRI, and allows the RF format to be modified as new standards emerge, without replacing or reprogramming the RRU.