1.28-Tb/s (32 $\times$ 40 Gb/s) Free-Space Optical WDM Transmission System

We successfully transmitted a 1.28-Tb/s (32 times 40 Gb/s) wavelength-division-multiplexed (WDM) signal over a free-space optic (FSO) link, for the first time. We used a novel pair of FSO terminals, transparently connected to optical fibers, to transmit/receive the WDM channels over a double-pass FSO path between two buildings (2 times 210 m). Limited penalty on all 40-Gb/s channels and high stability was observed. Furthermore, long-term measurements of the system performance indicate a high improvement in reliability, which makes it a promising alternative for future deployment.