660-nm GaInP-AlGaInP quantum-well laser diode structures with reduced vertical beam divergence angle

We propose a new layer design for 660-nm GaInP-AlGaInP quantum-well laser diodes employing a two-step n-cladding layer and demonstrate the feasibility of achieving a reduced vertical beam divergence angle of as low as 14.8/spl deg/ with a relatively small decrease in the optical confinement factor by theoretical simulations and experimental observations.