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Amplification of single channel and three Wavelength division multiplexing (WDM) channels with 16 and 64QAM modulated signals is demonstrated using an SOA with holding beam in the non-transparency wavelength to minimize phase distortion. We demonstrate an optical gain of 10 dB for single channel and for each channel in WDM operation. We also show that, the performance with holding beam can provide with minimal phase distortions a better bit-error rate value when compared to the linear regime of SOA operation for the same output power level.

We demonstrate an aberration-free, all-optical, ultra-fast oscilloscope based on the concept of Fourier-transformation with an optical time-lens. By combining the four-wave mixing time-lens with a Fourier-domain optical processor as the dispersive element we avoid aberrations associated with the traditional method of using lengths of fibre for the dispersive elements. We investigate the impact of aberrations due to third-order dispersion and inaccuracies in matching the Fourier-transform condition and demonstrate how these are overcome using the optical processor. The resolution of the oscilloscope is 750 fs. © 2010 Elsevier B.V. All rights reserved.

We demonstrate bit error rate improvement, corroborated by eye diagram measurements, of a (10 MHz) amplitude distorted 10 Gbit/s data signal in silicon photonic crystal waveguides. This demonstration exploits a power clamping nonlinear transfer function, provided by slow light enhancement of nonlinear absorption in these waveguides.

Femtosecond optical pulses of 1550-nm wavelength propagated in a dispersion-managed single-mode optical fibre link consisting of a 50-m dispersion compensation fibre, a 250-m dispersion-shifted fibre, and a 300-m standard dispersion fibre are characterised by high-sensitivity two-photon absorption frequency-resolved optical gating. Output pulse spectrogram shows pulse trailing wings in the short and long wavelength parts of the time-spectral distribution of pulse intensity, and implies dominance of third-order chromatic dispersion in ultrashort pulse propagation in the fibre link. Numerical simulation using a nonlinear pulse propagation equation, including the experimental characteristics of chromatic dispersion in the fibre link, produces a theoretical output pulse shape qualitatively consistent with that of output pulse shape reconstructed from the experimental pulse spectrogram.