Theoretical studies of aluminum-free RISAS and ARROW type lasers operating at 800 nm and 940 nm, respectively, are presented. At 800 nm, the electron leakage current over the hetero barriers leads to a sub-linear light-current characteristic. In order to obtain a high output power at moderate currents, either the losses must be kept as small as possible, or the barriers for the electrons must be increased, for example by higher p-doping. At 940 nm, the leakage current is not as problematic. In both RISAS and ARROW lasers, excess loss for the higher- order modes is needed to prevent them from lasing. The theoretical maximum single mode power of ARROW lasers obtained with a two-dimensional FEM-solution of the scalar wave equation is lower than found with the effective index method.