Unbalanced facet output power and large spot size in 1.3 mu m laser diodes is demonstrated using a laterally tapered active stripe. A slope efficiency as high as 0.46 W/A is obtained for the front facet of an uncoated LD. As a result of an unbalanced facet output power, the output power ratio of front to rear facets and the spot size of the LDs can be controlled simultaneously by tailoring the nontaper length in two sectional active geometries without an additional coating process.