Abstract: An optical bench for processing laser light in a laser system, including an optical bench housing, steering optics mounted within the optical bench housing for directing the laser light in a path from a laser light input to an output, and a first mechanism for monitoring power output of the laser light regardless of shifts in wavelength of the laser light. The steering optics includes a sampling filter mounted to the optical bench housing and positioned in the path of the laser light, wherein a first portion of the laser light is reflected to the output and a second portion of the laser light is transmitted to the first mechanism.

Abstract: A method for monitoring the thickness of a hermetic coating on an optical waveguide fiber is provided in which an interference pattern is produced by illuminating the fiber with a laser beam. A spatial frequency spectrum is generated for the interference pattern and a first component of that spectrum, corresponding to the outside diameter of the fiber, is identified. The magnitude of this component is inversely related to the thickness of the coating, i.e., the magnitude decreases as the coating thickness increases, and thus this magnitude can be used to monitor the thickness of the coating during, for example, the coating process. Effects of fluctuations in the power of the laser beam and/or movement of the fiber relative to that beam can be minimized by normalizing the magnitude of the first component by the magnitude of the DC component of the spatial frequency spectrum.