A laser apparatus uses a dysprosium doped chalcogenide glass fiber. The glass fiber has a laser pump operatively connected to it. The chalcogenide glass fiber is located in a laser cavity including one or more reflective elements such as a Bragg grating, a Bragg minor, a grating, and a non-doped fiber end face. The apparatus provides laser light output at a wavelength of about 4.3 μm to about 5.0 μm at a useful power level using laser light input at a wavelength of from about 1.7 μm to about 1.8 μm. Also disclosed is a method for providing laser light output at a wavelength of about 4.3 μm to about 5.0 μm using the apparatus of the invention.