Widely tunable laterally coupled distributed feedback laser diodes for multispecies gas analysis based on InAs/InGaAs quantum-dash material

Applying the concept of binary superimposed gratings, widely tunable single-mode laser diodes suitable for multispecies gas detection in the 1.8 microm wavelength range could be manufactured on InAs/InGaAs quantum dash-in-a-well material. A discrete wavelength tuning range of 21 nm as well as continuous tuning over 0.8 nm are demonstrated. Water and hydrogen chloride could be detected at absorption lines 13 nm apart.