Low-threshold GRIN-SCH AlGaInAs 1•55 μm quantum well buried ridge structure lasers grown by molecular beam epitaxy

Two-step MBE/MOVPE epitaxy buried ridge stripe GRIN-SCH quantum well lasers having MBE active structure consisting of GaInAs quantum wells and an AlGaInAs continuously graded confinement region have been fabricated and characterised. Devices operating at 1.55 μm wavelength with a low CW threshold current of 18.7 mA have been demonstrated. This figure is the best result obtained in the AlGaInAs system. A study of the intrinsic optical response of the active layer showed a very fast decay of the resonance oscillations. A good figure of the optical bandwidth move-out rate 3.9 GHz mW −1/2 has been observed