We demonstrate multiple-peaked switching in a nonlinear-optical loop mirror and present an experimental investigation of device cascading in the soliton regime based on a sequence of two independent nonlinear-optical loop mirrors. Cascading leads to an enhanced switching response with sharper switching edges, flattened peaks, and increased interpeak extinction ratios. We observe that pulses emerging from the cascade retain the sech2 temporal profile of a soliton with minimal degradation in the spectral characteristics.

The bleaching of the n=1 heavy-hole and light-hole exciton absorption has been studied at room temperature and zero bias in a strain-balanced InGaAs/InAsP multiple quantum well. Pump-probe spectroscopy was used to measure the decay of the light-hole absorption saturation, giving a hole lifetime of only 280 ps. As only 16 meV separates the light- and heavy-hole bands, the short escape time can be explained by thermalization between these bands followed by thermionic emission over the heavy-hole barrier. The saturation density was estimated to be 1×1016 cm−3; this is much lower than expected for tensile-strained wells where both heavy and light holes have large in-plane masses.

High-speed optical clock recovery, demultiplexing and data regeneration will be integral parts of any future photonic network based on high bit-rate OTDM. Much research has been conducted on devices that perform these functions, however to date each process has been demonstrated independently. A very promising method of all-optical switching is that of a semiconductor optical amplifier-based nonlinear optical loop mirror (SOA-NOLM). This has various advantages compared with the standard fiber NOLM, most notably low switching power, compact size and stability. We use the SOA-NOLM as an all-optical mixer in a classical phase-locked loop arrangement to achieve optical clock recovery, while at the same time achieving data regeneration in a single compact device.

Both linear and nonlinear absorption have been studied in a strain-balanced InAsP/InGaAs structure at room temperature. The sample, known as M552 was grown by solid source MBE. It consisted of 10 periods of 113 Å In0.44Ga0.56As/103 Å InAs0.2P0.8 in a pin diode configuration. X-ray diffraction indicated that there was 0.6% tensile strain in the InGaAs well and 0.6% compressive strain in the InAsP barrier. Using a 4 band k.p model which takes into account the strain we calculate the barriers heights seen by the n=l electron, heavy and light hole subbands to be 1O7 meV, 181 meV and 239 meV respectively

We demonstrate a dual-wavelength fibre laser system using chirped fibre Bragg gratings as reflectors and dispersive elements. The system produces two synchronized trains of soliton pulses with rms jitter of 620 fs.

We demonstrate a novel dual-wavelength erbium-fiber laser that uses a single nonlinear-optical loop mirror modulator to simultaneously modelock two cavities with chirped fiber Bragg gratings as end mirrors. We show that this configuration produces synchronized soliton pulse trains with an ultra-low RMS inter-pulse-stream timing jitter of 620 fs enabling application to multiwavelength systems at data rates in excess of 130 Gb/s.

We demonstrate bandpass nonlinear switching, using a novel device configuration based on a nonlinear-optical loop mirror and an in-fiber Bragg grating. Self-switching is demonstrated in the soliton regime by use of an asymmetrically arranged in-fiber Bragg grating as a wavelength-selective element. In addition, we adapt the configuration to perform efficient two-wavelength switching.

Ultrafast switching devices and high level processing architectures place two fundamental constraints on picosecond-regime data sources. The narrow spectral ranges of all-optical components for WDM [1] require multi-wavelength sources with output characteristics which are both arbitarily and accurately definable over a wide wavelength range. In addition, use of the nonlinear-optical loop mirror (NOLM) in higher level functional systems [2], in which pulse-streams symmetrically straddle the zero-dispersion wavelength, necessitates low levels of inter-pulse-stream jitter [3, 4].

We are investigating surface discharges as extreme ultraviolet (XUV) photon sources for preionizing anode surfaces of ion diodes in light-ion-fusion accelerators. Preionization is important both to control the diode impedance and to efficiently generate an ion beam. The surface discharges and their power feeds were constructed in a strip-line configuration to minimize overall system inductance. In...