Methods of preparing front and back facets of a diode laser include controlling an atmosphere within a first chamber, such that an oxygen content and a water vapor content are controlled to within predetermined levels and cleaving the diode laser from a wafer within the controlled atmosphere of the first chamber to form a native oxide layer hating a predetermined thickness on the front and back facets of the diode laser. After cleavage, the diode laser is transported from the first chamber to a second chamber within a controlled atmosphere, the native oxide layer on the front and back facets of the diode laser is partially removed, an amorphous surface layer is formed on the front and back facets of the diode laser, and the front and back facets of the diode laser are passivated.