Far-field scanning apparatus and method for rapid measurement of light source characteristics with high dynamic range

摘要

A method and apparatus for rapid measurements of far-field radiation profiles having a large dynamic range from an optical source is disclosed. Some embodiments of the apparatus include a collector coupled to a rotating hub so that the rotation of an entrance to the collector defines a plane, a detector coupled to receive light captured at the entrance to the collector, and detector electronics having a programmable gain coupled to receive a signal from the detector, Some embodiments may include a rotatable entrance mirror for reflecting light from the optical source into the plane of the entrance of the collector. In some embodiments, the optical source is fixed relative to the plane of the entrance of the collector. In some embodiments, the optical source is rotatable in the plane defined by the entrance of the collector. In some embodiments, the source can be an optical fiber. In some embodiments, the source can be a material irradiated by a laser. In order to obtain a large dynamic range, far-field data from the optical source is taken at a number of gain settings of the detector electronics and a compiled far-field radiation profile is constructed. Characterizing parameters for the optical source, such as fiber parameters for an optical fiber, can be calculated based on the compiled far-field radiation profile.