With simple optical geometries a separate resonant Fabry-Perot cavity can serve as an optical feedback element that forces a semiconductor laser automatically to lock its frequency optically to the cavity resonance. This method is used to stabilize laser frequencies and reduce linewidths by a factor of 1000 from 20 MHz to approximately 20 kHz.

We report and discuss our main results for the multimode dynamics of a Fabry-P erot laser in diierent situations above threshold: mode beating and mode-hopping. A Travelling Wave approximation has been used together with a model with an asymmetric dynamical gain for the semiconductor laser which captures important features needed for the understanding of multimode dynamics.

The power spectrum of the optical intensity at the output of a single-mode-fiber recirculating delay line driven by a multimode semiconductor laser is shown to exhibit a spectral structure with notches at zero frequency as well as at other multiples of 1/(loop delay). A theoretical model based on laser phase noise is suggested to explain the experimental data.

We present an actively mode-locked fiber ring laser that uses a single active semiconductor optical amplifier device to provide both gain and gain modulation from an external optical pulse train. The laser source generated 4.3-ps pulses at 20 GHz over a 16-nm tuning range and is stable against environmental changes and simple to build.

Plasmonic structures shape semiconductor laser beams. Left: A plasmonic collima-tor spreads out radiation from the sub-wavelength aperture into surface waves that are diffracted by the metallic grating to produce a low divergence beam. Right: A resonant optical antenna concentrates most of the laser light into a tens-of-nanometers size spot defined by the gap.

Multilongitudinal-mode dynamics in a semiconductor laser subject to optical injection are investigated both experimentally and numerically. We found that there are parameter regimes for which the slave laser hops into an adjacent longitudinal mode as we vary the detuning of the optical frequencies between the master and slave laser. A traveling wave model is used to numerically investigate the ...

We perform an analytical study of the external cavity modes of a semiconductor laser subject to conventional optical feedback as modeled by the well-known Lang-Kobayashi equations. Specifically, the bifurcation set is derived in the threedimensional parameter space of feedback phase, feedback strength and pump current of the laser. Different open regions in this space correspond to different nu...

Optically pumped semiconductor disk lasers (OPSDLs) with extended cavities are surfaceemitting laser devices which efficiently convert the low-beam-quality emission of a pump laser to a high-beam-quality circular non-astigmatic laser emission. Furthermore, the extended cavity can be utilized for intra-cavity second harmonic generation by insertion of nonlinear optical crystals. By that way, the...

We experimentally study the response of an injection-locked quantum dot semiconductor laser in the excitable regime to perturbations from an external, incoherent laser. We show that excitable pulses may be triggered both for perturbation wavelengths close to that of the quantum dot device and wavelengths detuned even by a few tens of nanometers.

Low-frequency fluctuations, which are typical irregular oscillations in edge-emitting semiconductor lasers, are experimentally observed for the y-polarization mode (y is the direction along the optical axis of a laser material) in a vertical-cavity surface-emitting laser with optical feedback.