High-capacity dynamic indoor network employing optical-wireless and 60-GHz radio techniques

We demonstrate a hybrid radio-optical wireless communication system using a photonic integrated all-optical-cross-connect (OXC) chip to realize a highly reconfigurable and reliable bidirectional indoor wireless network that provides the ultimate capacity per user. By remote wavelength-tuning, narrow optical beams are directed to the users employing a passive two-dimensional beam steering module fixed at the ceiling in each room. Robustness regarding line-of-sight issues is achieved by implementing 60-GHz radio protection channels generated optically using a shared amplitude modulator via the OXC chip. The use of a 35-GHz reflective electroabsorption modulator (REAM) monolithically integrated with a semiconductor optical amplifier (SOA) chip is proposed for upstream wideband analog applications. The REAM-SOA provides similar performances as an REAM, but over a wide range of input optical powers and wavelengths. This mitigates the need for accurate control of the input signal, especially at remote sites where simplicity is strictly required. System experiments showed downstream optical-wireless transmission capacities of up to 35 Gb/s per user and 60-GHz protection channels with a capacity of 20 Gb/s. Upstream radio-over-fiber transmission rates of more than 35 Gb/s have also been achieved.