ABSTRACT
Two VCSELs placed facing each other with one biased chip while the second chip is unbiased is shown as a promising alternative to the popularly used conventional SESAM mode-locked VECSEL to generate mode-locked pulses. We propose a theoretical model using time-delay differential rate equations and numerically show that the proposed dual-laser configuration functions as a typical gain-absorber system. Parameter space defined by laser facet reflectivities and current are used to show general trends in the exhibited nonlinear dynamics and pulsed solutions.
ABSTRACT
A simple, versatile model for the dynamics of electrically and optically pumped vertical-external-cavity surface-emitting lasers, which are mode locked by a semiconductor saturable-absorber mirror, is presented. The difference between the laser operation in the linear and folded cavity, as well as the potential for a colliding pulse operation, are studied.
ABSTRACT
A simplest saturable absorber, in the form of an unpumped section, is introduced into a Fabry-Perot semiconductor laser with a strongly asymmetric broadened waveguide structure incorporating a relatively thick (80 nm) active layer. This allows for suppression of trailing oscillations and a decrease in the optical pulse width compared to the uniformly biased structure. Single optical pulses of ~80 ps full width at half maximum (FWHM) and ~35 W peak power (~3 nJ pulse energy, E(opt)), practically without trailing edge oscillations, were experimentally achieved under room temperature conditions by absorber-assisted gain-switching, using pumping current pulses of ~1.3 ns FWHM and ~17 A amplitude. The laser emission has a narrow (13 degrees FWHM in the transverse direction) far field.
ABSTRACT
We characterized the reflectivity and the modal discrimination of intracavity reflectors (ICRs) with different numbers of slots and presented harmonic mode-locking operation of a monolithic semiconductor laser comprising a compound cavity formed by a single deeply etched slot ICR fabricated from 1.55 µm AlGaInAs strained quantum well material. Gaussian pulses were generated at a 161.8 GHz repetition rate with a pulse duration of 1.67 ps and a time-bandwidth product of 0.81.
