Red GaInP/AlGaInP microsquare lasers with output waveguide are fabricated by standard photolithography and inductively coupled plasma(ICP) etching techniques.The square microcavity lasers are operated at low temperature.For a 10-μm-side square microlaser with a 30-μm-long and 1.5-μm-wide output waveguide,the mode interval of 1.3 nm is observed in the amplified spontaneous emission spectra at room temperature,which corresponds to the longitudinal mode interval of the Fabry-Pérot(F-P) cavity that ...