Injection $GaInPAs/InP$ heterojunction laser with $6-7^\circ$ output divergence, emitting nonwaveguide modes

A heterojunction laser emitting at 1.255$\mu m$ was constructed. The active layer was inclined at an angle of $13^\circ$ relative to the resonator axis. This inclination suppressed excitation of waveguide modes and ensured generation of nonwaveguide modes with an output divergence of $6-7^\circ$. The minimum threshold current density at room temperature was 18 kA/cm${}^2$, which was only 3 times higher than in similar waveguide lasers.