Design and Characterisation of Terabit/s Capable Compact Localisation and Beam-Steering Terminals for Fiber-Wireless-Fiber Links

This article presents the design, implementation, and characterisation of compact fiber-wireless-fiber (FWF) localisation and beam-steering terminals, which provide a bi-directional free-space connection between fiber optic transceivers. The use of simple mirror based beam-steering, with high localisation accuracy in both steering axes enables ultra-high data rate transmission and practical indoor coverage. The auto-aligned terminals have a tracking accuracy of 0.02o, a full angle field-of-view (FoV) of 50o, a tracking latency of 200 ms, and work at wavelengths between 1300–1700 nm. In an offline data processing experimental setup, 1 Tbit/s free-space transmission capability is demonstrated over a 2.54 m2 coverage area using ten wavelength division multiplexed PAM-4 signals. Further, full-duplex, real-time, data transmission using off-the-shelf small form-factor pluggable (SFP) optical transceivers is also demonstrated for virtual reality (VR) application. Here, using standard 10 G SFP+ transceivers without the use of any pre/post optical amplification, the auto-aligned FWF terminals achieve 4.9 m2 localisation and 3.14 m2 bidirectional communications coverage over a range of $\sim$4 m.