Novel fabrication-tolerant twin-guide laser structure with an external passive waveguide

The authors propose a novel quasi-symmetrical twin-guide GaAs/AlGaAs laser structure (QSTGL) with a low-loss external passive waveguide. The device is tolerant to fabrication misalignment and therefore well suited for monolithic integration. Threshold current densities of less than 1.1 kA/cm² and a coupling efficiency between 70 and 80% into the low-loss passive waveguide are achieved