Continuous-wave operation of type-I quantum well DFB laser diodes emitting in 3.4 μm wavelength range around room temperature

Distributed feedback (DFB) laser diodes based on the concept of lateral metal gratings fabricated on type-I quantum well GaInAsSb/AlGaInAsSb material are presented. Monomode emission in the 3.4 µm wavelength range was achieved for the first time for a GaSb based DFB laser diode. Excellent sidemode suppression ratios beyond 30 dB are demonstrated in combination with a modehop-free tuning range around 8.5 nm. Using a specially developed polymer-free DFB processing route allowing improved heat dissipation, laser operation in continuous-wave mode was observed at temperatures up to around 20°C.