M. S. Erkilinc

Nyquist-shaped dispersion-precompensated subcarrier modulation with direct detection for spectrally-efficient WDM transmission

We report on the first experimental demonstration of 14 Gb/s direct detection single-sideband subcarrier modulated Nyquist QPSK transmission. Using electronic pre-compensation, transmission over 800 km of dispersion-uncompensated standard single-mode fiber was achieved.

Direct-detection 16-QAM Nyquist-shaped subcarrier modulation with SSBI mitigation

We report on the first experimental demonstration of direct-detection dispersion pre-compensated single-sideband Nyquist-pulse-shaped 16-QAM subcarrier modulation (N-SCM) signal transmission using a signal-signal beat interference (SSBI) cancellation technique. The improvement in the system performance through the use of SSBI cancellation, which mitigates the nonlinear distortion caused by the square-law detection, was quantified by simulations and experiments for a 25 Gb/s N-SCM signal occupying an optical bandwidth of 8.75 GHz. A reduction of 3.6 dB in the back-to-back required OSNR at the 7% overhead HD-FEC threshold was achieved. A 1.1 dB increase in the Q2-factor after transmission over 800 km of uncompensated standard SMF was measured.

Simplified DSP-based signal-signal beat interference mitigation for direct-detection subcarrier modulation

We proposed a novel SSBI mitigation technique with significantly lower DSP complexity. It was experimentally tested in 7×25 Gb/s WDM DD SSB 16-QAM N-SCM signal transmission over 480 km SSMF with a net ISD of 2.4 (b/s)/Hz.

Effect of clipping on the performance of Nyquist-shaped dispersion-precompensated subcarrier modulation transmission with direct detection

We investigate the effect of signal waveform symmetric clipping on the performance of dispersion-precompensated subcarrier modulated Nyquist-QPSK in uncompensated direct detection links. OSNR gains of 0.7 dB and 1.2 dB are achieved over 400 and 800 km of SSMF, respectively.

Performance limits of spectrally-efficient WDM direct-detection SSB Nyquist subcarrier modulation with signal-signal beat interference cancellation

We carried out a simulation-based study assessing the performance of WDM direct-detection dispersion pre-compensated single-sideband (SSB) Nyquist-pulse-shaped QAM subcarrier modulated (N-SCM) systems using a receiver-based signal-signal beat interference (SSBI) cancellation technique. The performance improvement with SSBI cancellation, which compensates for the nonlinear distortion caused by square-law detection, was quantified for 9 × 112 Gb/s 16-QAM and 9 × 224 Gb/s 64-QAM N-SCM signals with net optical information spectral densities (ISD) of 2.1 (b/s)/Hz and 4.1 (b/s)/Hz respectively. The simulations predict significant reductions in the required OSNR, and increases of up to 45% in transmission distance over uncompensated standard single-mode fibre (SSMF) using the SSBI compensation technique.