title: Demonstration and performance investigation of all-optical OFDM systems based on arrayed waveguide gratings.
abstract: We experimentally demonstrate an 8 x 12.5 Gbit/s all-optical orthogonal frequency-division multiplexing (AO-OFDM) system using arrayed waveguide gratings (AWGs), which perform discrete Fourier transform (DFT) and inverse DFT (IDFT) of a signal directly in the optical domain. The experimental results show that frequency orthogonality of OFDM sub-channels is degraded in the AWG due to the slab-diffraction effect. To restore the frequency orthogonality and improve the system performance, we propose and demonstrate a waveform reshaping scheme, that improve the bit-error-rate (BER) from 10(-4) to 10(-6). We also experimentally investigate the influence of frequency mismatch between the OFDM signal and AWG at the receiver. The measured BER shows a serious degradation from 10(-6) to 10(-4) in case of ± 1.88 GHz frequency mismatch. To keep the BER under 10(-5), the frequency mismatch should be smaller than ± 0.5 GHz ( ± 4% of the channel spacing).
authors.affiliation: National Institute of Information and Communications Technology, Tokyo, Japan. sshimizu@nict.go.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Shimizu
authors.forename: Gabriella
authors.initials: G
authors.lastname: Cincotti
authors.forename: Naoya
authors.initials: N
authors.lastname: Wada