Transverse mode stabilized InGaAsP/InP (λ = 1.3 µm) piano-convex waveguide lasers

Guiding mechanisms and lasing characteristics of an InGaAsP/InP 1.3 μm band piano-convex waveguide (PCW) laser are described. The laser structure is fabricated by a single-step liquid phase epitaxial (LPE) growth on a grooved substrate. The refractive index guiding caused by the lateral thickness variations of a waveguide layer adjacent to the active layer is investigated both theoretically and experimentally. Lasers with an adequate refractive index difference and groove width showed stable fundamental mode operation up to two times the threshold current level.