A linearizing transformation for the Korteweg-de Vries equation; generalizations to higher-dimensional nonlinear partial differential equations

It is shown that the Korteweg–de Vries (KdV) equation can be transformed into an ordinary linear partial differential equation in the wave number domain. Explicit solutions of the KdV equation can be obtained by subsequently solving this linear differential equation and by applying a cascade of (nonlinear) transformations to the solution of the linear differential equation. It is also shown that similar concepts apply to the nonlinear Schrödinger equation. The role of symmetry is discussed. Finally, the procedure which is followed in the one-dimensional cases is successfully applied to find special solutions of higher-dimensional nonlinear partial differential equations

Error-propagation in weakly nonlinear inverse problems

In applications of inversion methods to real data, nonlinear inverse problems are often simplied to more easily solvable linearized inverse problems. By doing so one introduces an error made by the linearization. Nonlinear inverse methods are more accurate because the methods that are used are more correct from a physical point of view. However, if data are used that have a statistical error, nonlinear inversion methods lead to a bias in the retrieved model parameters, caused the by nonlinear propagation of errors. If the bias in the estimated model parameters is larger than the linearization error, a linearized inverse problem leads to better estimation of the model parameter. In this paper the error-propagation is investigated for inversion methods that account the nonlinearity quadratically

Optical RF tone in-band labeling for large-scale and low-latency optical packet switches

We propose an RF tone in-band labeling technique that is able to support large-scale and low-latency optical packet switch. This approach is based on N in-band wavelengths, each carrying M radio frequency (RF) tones. The wavelengths and the tones have a binary value, and are able to encode 2N×M possible routing address. We develop an optical label processor for the RF tone in-band optical label based on parallel and asynchronous processing. It allows the optical packet switch with an exponential increase of number of ports at the expense of limited increase in the latency and the complexity. By using RF tone in-band labeling technique, we demonstrate error free (bit error rat

WDM monitoring technique using adaptive blind signal separation

We present a cost-effective method of monitoring the performance of wavelength-division-multiplexed (WDM) channels. The method is based on simple optical signal processing in combination with electronic signal processing. The photocurrent of a detected (multi-channel) optical signal is analysed using an adaptive blind signal separation method. A maximum data decorrelation criterion is used to separate the WDM channels. We show experimentally that four WDM channels can be reconstructed accurately by this numerical method

Wavelength conversion employing 120-fs optical pulses in a SOA-based nonlinear polarization switch

We demonstrate wavelength conversion based on nonlinear polarization rotation driven by ultrafast carrier relaxation in an InGaAsP-InGaAs multiquantum-well semiconductor optical amplifier. We use a continuous-wave (CW) probe beam at a center wavelength of 1555 nm, and a control pulse of duration of 120 fs at a center wavelength of 1520 nm. We have investigated wavelength conversion for different injection currents and for different control pulse energies. We show that a conversion efficiency of 12 dB can be obtained for control pulse energies of 10 pJ

All-optical label swapping of in-band addresses and 160 Gbit/s data packets

A 1×4 all-optical packet switch is presented, based on an optical label swapping technique that utilises a scalable label processor and a label rewriter with 'on the fly' operation. Experimental results show error-free packet switching with a data payload at 160Gbit/s. The label erasing and new label insertion operation introduces 0.5dB of power penalty. These results indicate a potential utilisation of the presented technique in a multi-hop packet switched network

All-optical label swapping techniques for data packets beyond 160 Gb/s

We present two paradigms to realize all-optical packet switches, and report experimental results showing the routing operation of the 160 Gb/s packets and beyond. Photonic integrated sub-systems required to implement the packet switch are reviewed. © 2009 IEEE

Fast and scalable optical packet switch architecture for computer communication networks

We present a novel low latency, high throughput and scalable optical packet switch (UPS) capable to optically interconnect hundreds of input/output ports. We focus on a strictly non-blocking Spanke architecture with contention resolution based on wavelength conversion. Highly distributed control of the UPS reduces the switching time to few nanoseconds regardless the amount of inputs/outputs. Queuing node analysis (mean values analysis) of input buffers in a computer communication network with windowflow control confirms that the new architecture, unlike rearrangeable nonblocking (i.e. Benes) architecture, can operate with low latency and high throughput with a very large amount of input/output ports

Low penalty 80 Gb/s non-inverted wavelength conversion using a broad rectangular shaped optical filter

We demonstrate non-inverted wavelength conversion at 80 Gb/s based on cross-phase modulation in a SOA. Using a flat-top 6 nm broad filter with sharp roll-off we achieve a penalty of only 0.5 dB