An edge emitting semiconductor laser includes a semiconductor body including a waveguide region, the waveguide region including first and second waveguide layers and an active layer arranged between the first and second waveguide layers, that generates laser radiation; the waveguide region is arranged between a first and second cladding layers disposed downstream of the waveguide region; a phase structure for selection of lateral modes of the laser radiation emitted by the active layer, wherein the phase structure includes at least one cutout extending from a top side of the semiconductor body into the second cladding layer; at least one first intermediate layer composed of a semiconductor material different from that of the second cladding layer embedded into the second cladding layer; and the cutout at least partly extends from the top side into the first intermediate layer; the second cladding layer contains a first partial layer adjoining the waveguide region.

An aluminium gallium indium phosphide (AlGaInP)-based semiconductor laser device is provided. On a main surface of a semiconductor substrate formed of n-type GaAs (gallium arsenide), from the bottom layer, an n-type buffer layer, an n-type cladding layer formed of an AlGaInP-based semiconductor containing silicon (Si) as a dopant, an active layer, a p-type cladding layer formed of an AlGaInP-based semiconductor containing magnesium (Mg) or zinc (Zn) as a dopant, an etching stopper layer, and a p-type contact layer are formed. Here, when an Al composition ratio x of the AlGaInP-based semiconductor is taken as a composition ratio of Al and Ga defined as (Al.sub.xGa.sub.1-x).sub.0.5In.sub.0.5P, a composition of the n-type cladding layer is expressed as (Al.sub.xnGa.sub.1-xn).sub.0.5In.sub.0.5P (0.9<xn<1) and a composition of the p-type cladding layer is expressed as (Al.sub.xpGa.sub.1-xp).sub.0.5In.sub.0.5P (0.9<xp1), and xn and xp satisfy a relationship of xn<xp.