Hybrid OFDM experimentation based on arrayed waveguide grating for all-optical FFT implementation in PON architecture

A hybrid optical frequency division multiplexing (OFDM) system based on the electrical generation of the OFDM signal at the transmitter and on the all-optical demultiplexing of the OFDM subcarriers is experimentally demonstrated by exploiting a purposely designed arrayed waveguide grating (AWG) with 12.5 GHz frequency spacing. The AWG passively and all-optically processes a 3-subcarrier OFDM signal with fast Fourier transform functionalities, demultiplexing it into three 12.5 Gbit/s on-off keyed data at the corresponding output ports, which are then connected to the optical network users. Transmission over a 40 km feeder link is experimentally demonstrated. Taking into account the AWG´s available 16 ports and four 3-subcarrier OFDM signal generators modulating independent wavelength carriers, a passive optical network (PON) architecture can be realised serving 12 optical network units with 150 Gbit/s total aggregate downstream capacity.