Edge-emitting laser diodes having mirror facets include passivation coatings that are conditioned using an ex-situ process to condition the insulating material used to form the passivation layer. An external energy source (laser, flash lamp, e-beam) is utilized to irradiate the material at a given dosage and for a period of time sufficient to condition the complete thickness of passivation layer. This ex-situ laser treatment is applied to the layers covering both facets of the laser diode (which may comprise both the passivation layers and the coating layers) to stabilize the entire facet overlay. Importantly, the ex-situ process can be performed while the devices are still in bar form.