The effect of (NH4)(2)S-x treatment of the facet of InGaAs/AIGaAs ridge waveguide (RW) laser diodes on the nonradiative current and catastrophic optical damage (GOD) level is reported. Using the power-voltage-current (P-V-I) characteristics of the electroluminescence at low injection levels, changes in the density of surface states at the laser facets are described. (C) 1996 American Institute of Physics.