Full-duplex analog WiFi transport over RSOA-based wavelength-reused digital passive optical networks

We experimentally demonstrated the transparent convergence of distributed antenna system in a digital wavelength division multiplexed passive optical network system employing reflective semiconductor optical amplifier (RSOA) at the remote antenna unit (RAU). The spurious free dynamic range and frequency response of the RSOA is measured to meet WiFi´s requirements. RSOA´s electrical-to-optical conversion efficiency improves significantly by down converting the WiFi signal to intermediate frequency band. By incorporating the up/down mixer in Central Office and RAU, we experimentally achieve full-duplex WiFi transmission along with 1 Gb/s downlink digital on-off-keying signal in single mode fiber up to 15 km (64QAM), 40 km (16QAM), and 60 km (QPSK) with 1 meter wireless path working in half-duplex mode. The bit-error-rate below the forward error correction threshold (2 × 10⁻³) is observed in all cases whereas the 1 Gb/s digital downlink signal is error-free up to 20 km of fiber.