Injection laser

An injection laser comprising at least one gain region having a longitudinal gain axis and outputting laser radiation defined by an outflow angle φ, said injection laser comprising:

• a laser heterostructure comprising:
• an active layer forming said at least one gain region;
• cladding layers comprising at least one layer having a refractive index, and
• at least one radiation inflow region adjoining said laser heterostructure comprising at least one portion that is transparent to said laser radiation, has a refractive index nRIR, and is located on at least one side of said active layer, said radiation inflow region including at least one optical facet, an outer surface, and an inner surface, said optical facet being oriented at an angle of inclination ψ with respect to a plane perpendicular to said longitudinal gain axis;
• and
• reflectors that together form an optical resonator at least part of which coincides with at least part of said radiation inflow region and at least part of said gain region,
• wherein said laser heterostructure and said adjoining radiation inflow region together have an effective refractive index neff such that
• nRIR exceeds neff;
• arccos(neff/nRIR)≦arccos(neff-min/nRIR);
• and
• neff-min is greater than nmin,
• where neff-min is the minimum value of neff for laser heterostructures with radiation inflow regions that produce outflow of radiation from the active layer into the radiation inflow region, and nmin is the smallest of the refractive indices in the cladding layers of the heterostructure.