A new high-power, narrow-beam transverse-mode stabilized semiconductor laser at 1.5 μm: the heteroepitaxial ridge-overgrown laser

Abstract

We proposed and demonstrated the operation of a new laser structure: the heteroepitaxial ridge-overgrown (HRO) laser. The laser growth involves two epitaxial growths with ridge overgrowths through an oxide defined stripe to form the strip loaded waveguide of the laser with automatic alignment of the current confinement through the stripe. Characteristics of the 1.5-μm wavelength GaInAsP HRO lasers include high output powers of ∼50 mW/facet under pulsed operation and narrow beam divergence of ∼12° (half-power full width) operating in the fundamental transverse mode in the junction plane. The light-current characteristic is linear up to ∼30 mW/facet. The current threshold is as low as 70 mA. The external differential quantum efficiencies from both facets are 25%–35%. Because no reverse-biased pn junction was used for current injection confinement, very fast optical pulse response of 160 ps (half-power full width, detection limited) was obtained.