Limitations of two-dimensional passive waveguide model for λ=980 nm Al-free ridge waveguide lasers

The performance characteristics of ridge waveguide InGaAs/InGaAsP/GaAs strained quantum well lasers emitting at 980 nm are reported. Factors limiting the validity of a passive waveguide two-dimensional approximation model are investigated. In particular, is was found that a gain-guiding effect is responsible for the fundamental mode stabilization and lateral far-field broadening. Ridge waveguide laser parameters which influence the stability of lateral single mode operation are discussed. An output power of 180 mW in spatial single mode operation was attained, and it was limited by catastrophic optical damage of the mirror facet.