Distribution and spatial coherence of radiation fields of InGaAsP/lnP double-heterostructure separate-confinement lasers emitting at λ = 1.3 μm

An investigation was made of the optical characteristics of wide (a = 60 μm) stripe InGaAs/InP double-heterostructure lasers emitting at λ = 1.3 μm. These lasers were made by liquid phase epitaxy. They had separate confinement and a wide strip. In the (1–5 )I_p range of pump currents, where I_p is the threshold current, the optical properties were due to superposition of the zeroth mode and several transverse modes with indices 1–4. The dimensions of the lasing region of each of the modes were comparable with the strip width. The investigated lasers were characterized by a much more stable distribution of radiation in the near-field zone in the plane of a structure than conventional double-heterostructure heterolasers without separate confinement but made under similar technological conditions.