Butt joined integrated GaInAsP MQW laser and waveguide grown by selective CBE

We report the successful realization of 1.55 μm buried MQW SCH lasers with all quaternary quantum wells and butt joint between laser and waveguide structure by the selective in-filling growth of laser structures into etched grooves. The grooves were etched into the basic layers, e.g., InP or the waveguide structure, grown in a preceding epitaxial run. These structures were contacted and cleaved to stripe lasers of different length and width. The electrical and optical performance of laser diodes for different substrate orientation, aperture of grooves and basic layer design were studied. 220 μm long buried 6 QW lasers grown into 3 μm wide grooves, etched in an exactly oriented substrate showed threshold currents less than 10 mA for cw operation at 20°C. 6 QW SCH laser structures were grown into basic waveguide layers, giving a butt joint. By comparing the threshold current of butt joined and cleaved lasers, coupling coefficients between 60% to 80% were estimated