Daan Lenstra

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We use a new rate-equation model for the propagation of sub-picosecond polarized optical pulses in a semiconductor optical amplifier (SOA). This model is based on the decomposition of the polarized optical field into TE and TM components that interact via the gain saturation, and accounts for two-photon absorption, free-carrier absorption, selfand(More)
Abstract. 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(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)
We investigate an all-optical switch that is operated by the nonlinear phase-shift introduced by optical pulses with duration of 200 fs in a semiconductor optical amplifier (SOAs). The gate is made out of a commercially available InGaAsP–InGaAs multi-quantum-well (MQW) SOA placed in a Mach–Zehnder interferometer. We have measured the nonlinear phase-shift(More)
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 consider two identical, mutually delay-coupled semiconductor lasers and show that their compound laser modes (CLMs) — the basic continuous wave solutions — depend rather sensitively on the pump current of the lasers. Specifically, we show with figures and accompanying animations how the underlying CLM structure and the associated locking region, where(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 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)
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)
A single-mode diode laser subject to reflections from an externally pumped phase-conjugate mirror is theoretically investigated by using a rate-equation approach. In the phase plane defined by the amount of feedback and the frequency detuning between diode laser and phase-conjugate mirror, we found an island of locked steadystate behavior, surrounded by(More)