We report the shortest pulses (290 fs) obtained directly from semiconductor lasers. These were achieved using a passively mode-locked semiconductor disk laser with a graded-gap barrier design in the gain section operating near 1036 nm.

A passively mode-locked semiconductor disk laser employing a graded-gap-barrier design in the gain section is presented. The all-semiconductor laser generates transform-limited pulses as short as 290 fs at 1036 nm.

Transform-limited pulses as short as 290 fs at 1036 nm are generated by a diode-pumped semiconductor disk laser. The all-semiconductor laser employs a graded-gap-barrier design in the gain section. A fast saturable absorber mirror serves as a passive mode-locker. No further elements for internal or external dispersion control are required.

Results of an all-optical analysis of basic semiconductor parameters such as carrier mobilities, lifetimes, and electron spin relaxation time of implanted In0.25Ga0.75As∕GaAs multiple quantum well saturable-absorber structures for the 1060nm spectral range are presented. These parameters are determined in a wide range of optical excitation, even at the practical operation point of such devices. This is accomplished by the application of polarization-resolved pump-probe and four-wave-mixing spectroscopies. The all-optical approach allows the determination of mobilities and spin relaxation time from the same experiments and points to the D’yakonov-Perel mechanism to govern the electron spin relaxation at room temperature.

We theoretically analyze and experimentally demonstrate a semiconductor device that simultaneously acts as a mode-locker and provides substantial dispersion compensation, enabling the construction of extremely compact femtosecond lasers.

The authors investigate the spectral tuning of the exciton resonance of a surface quantum well saturable absorber mirror for the generation of subpicosecond pulses, employing an optically pumped semiconductor disk laser in the 1μm spectral range. The all-semiconductor laser generates transform-limited pulses as short as 590fs at a 3GHz repetition rate and an output power of 30mW. The pulse duration of the mode-locked laser was supported by the fast relaxation time of the saturable absorber of 1.0ps.

We discuss carefully characterized semiconductor disk lasers with high spatial and spectral homogeneity, exhibiting 23% conversion efficiency and a 540-mW output power for cw operation. Passive mode-locking with 1.5-ps pulse duration is also demonstrated.

Summary form only given. This paper reports continuous-wave (cw) and passive mode-locked laser operation of diode-pumped semiconductor disk lasers based on gain sections with step and graded index designs, each containing 6 InGaAs quantum wells. Mode-locked laser operation is achieved applying both structures, using a V-shaped cavity including a fast saturable semiconductor absorber mirror. Results show that the graded index structure exhibits clear advantages over the step index structure in cw-laser operation with respect to the saturation of the absorption. However, for mode-locked operation, shorter pulses are generated using the step index structure.