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We demonstrate the generation of sub-picosecond optical pulses using a semiconductor optical amplifier (SOA) and a linear polarizer placed in a ring-laser configuration. Nonlinear polarization rotation in the SOA serves as the passive mode-locking mechanism. The ring cavity generates pulses with duration below 800 fs (FWHM) at a repetition rate of 14 MHz.(More)
We present a theoretical study of unnested period-doubling islands in three-dimensional rate equations modeling a semiconductor laser subject to external optical injection. In this phenomenon successive curves of period doublings are not arranged in nicely nested islands, but intersect each other. This overall structure is globally organized by several(More)
We consider a model of two mutually delay-coupled semiconductor lasers in a face to face configuration. The lasers are coherently coupled via their optical fields, where the time delay τ arises from the finite propagation time of the light from one laser to the other. This system is described well by single mode rate equations, which are a system of delay(More)
We present an experimental and theoretical study of the optical transmission of a thin metal screen perforated by two subwavelength slits, separated by many optical wavelengths. The total intensity of the far-field double-slit pattern is shown to be reduced or enhanced as a function of the wavelength of the incident light beam. This modulation is attributed(More)
We show that a laser with a saturable absorber, described by the Yamada model, displays excitability just below threshold. A small perturbation, for example, a small input pulse, can trigger a single high output pulse, after which the system relaxes back to the off state. In order to study possible applications, such as pulse reshaping and clock recovery,(More)
Optical power spectra obtained from experiments or from numerical simulations are probabilistic in nature. When fitting such spectra to few-parameter analytical line shapes, the results from a weighted nonlinear least squares fit are significantly better than those from an unweighted fit. This is demonstrated by fitting a Lorentzian to directly simulated(More)
An optically injected semiconductor laser can produce excitable multipulses. Homoclinic bifurcation curves confine experimentally accessible regions in parameter space where the laser emits a certain number of pulses after being triggered from its steady state by a single perturbation. This phenomenon is organized by a generic codimension-two homoclinic(More)
Left ventricular (LV) outflow tract (OT) obstruction can be treacherous in any form of atrioventricular (AV) septal defect. The properties of the LVOT were investigated echocardiographically in 64 patients with separate valve orifices ("ostium primum atrial septal defect") who had survived corrective surgery. M-mode and cross-sectional echocardiographic(More)
We investigate all-optical switching in a multi-quantum-well semiconductor optical amplifier-based nonlinear polarization switch using optical pulses with duration of 200 fs at a central wavelength of 1520 nm. We show full recovery of the switch within 600 fs, in both the gain and absorption regime. We discuss the switching and recovery mechanisms using(More)