Quantum-well ridge GaAs/AlGaAs heterostructure lasers are studied at high pump currents. It is shown that their catastrophic optical damage (COD) is preceded, as a rule, by a giant kink caused by the collapse of a waveguide in a horizontal plane. It is found that, by increasing the coating thickness of the output end-face of a diode by preparing an intermediate ZnSe layer between the cleaved output end-face of the diode and a coating forming the output mirror of the laser, it is possible to increase the COD threshold by a factor of 1.5–2. This optical strengthening occurs because the ZnSe layer provides an additional channel for heat sink from the overheated output face.