HIGH-RESOLUTION VARIABLE OPTICAL ATTENUATOR WITH MECHANICAL ADJUSTMENT

摘要

A mechanically-adjustable variable optical attenuator (20) includes a beam attenuator (32) shaped as a concave quasi-cone. The beam attenuator has a sharp tip (38) and a base (54), and can be rotationally symmetric with respect to a central axis (60) extending between the tip (38) and the base (54). The beam attenuator (32) is positioned with its central axis (60) perpendicular to the direction of the light beam (50) to be attenuated. The extent of the beam attenuator (32) obstructing the light beam (50) is varied by moving the beam attenuator (32) into and out of the light beam (50). The inwardly-curving, quasi-cone shape of the beam attenuator (32) allows achieving a high resolution while limiting the beam attenuator size.