A Flexible Bidirectional Fiber-FSO-5G Wireless Convergent System

A flexible bidirectional fiber-free-space optical (FSO)-fifth-generation (5G) wireless convergent system with 1-Gb/s/4.5-GHz sub-6 GHz and 10-Gb/s/28-GHz millimeter-wave (MMW) (downstream), as well as 10-Gb/s/24-GHz MMW (upstream) 5G hybrid data signals is built, employing a vertical cavity surface emitting laser (VCSEL)-based wavelength selector and a remotely injection-locked distributed feedback laser diode (DFB LD) for presentation. It is the first to adopt a VCSEL-based wavelength selector to adaptively provide 5G applications and an injection-locked DFB LD to perform a phase modulation-to-intensity modulation transformation with an optical-to-electrical conversion. Good bit error rate performance and acceptable eye diagrams are achieved over 25 km single-mode fiber transport, 600 m FSO link, and 10 m/4 m RF wireless transmission. Such demonstrated fiber-FSO-5G wireless convergent system is a promising one toward optical-based long-haul networks at comparatively high-speed operations. It exhibits an excellent convergence not only due to its development for incorporating optical fiber with optical/5G wireless networks, but also due to its enhancement for flexible two-way high-speed and long-haul communications.