Broad spectral bandwidth semiconductor lasers

Wavelength-tuned semiconductor lasers have been realised in a GaAs/AlGaAs structure in which the active layer contains three different sizes of quantum well. Extended cavity operation with an external grating has enabled a useful tuning range of 88 nm (778 – 866 nm) to be demonstrated while the threshold current varied by no more than 20 mA about a nominal value of 100 mA across the tuning range. Alternatively, the wide spectral bandwidth of the structure could be used in very short-pulse modelocked lasers.