Semiconductor optical element for external cavity laser

Abstract

The present invention provides a semiconductor optical element applicable to an EC-LD or an SLD, and an external cavity laser having the semiconductor optical element. The semiconductor optical element has a pair of cleavage surfaces, and comprises a semiconductor substratehaving a base surface and a planer structure provided on the base surface and provided with a waveguideG having an active layer. The waveguideG has an end surface with low reflectivity and another end surface with certain reflectivity. The waveguideG includes an end portion having a first optical axis in the vicinity of the first end surfaceTand an end portion having a second optical axis in the vicinity of the second end surfaceT, the first optical axis being inclined at a first angle Φother than zero degree with respect to a normal to the first end surfaceT, the second optical axis being inclined at a second angle Φother than zero degree with respect to a normal to the second end surfaceT, the first angle Φbeing different from the second angle Φ. The end portion of the waveguideG is different in width from the other end portion of the waveguideG.