Abstract: Distortion introduced by an imaging system is characterized by positioning a generally cylindrical object and imaging optics in a first relative angular position about an axis of rotation that substantially coincides with the longitudinal axis of the object and employing the imaging optics to image the end face of the object on a detector. First and second definitions of the shape of the image of the periphery of the end face of the object are extracted from image data provided by the detector when the object and the imaging optics are in first and second relative angular positions. The first and second definitions are compared.

Abstract: Concentricity of an optical fiber segment is determined by positioning the fiber segment with its central axis substantially coinciding with an axis of rotation, the fiber segment being in a first angular position about the axis of rotation, imaging the end face of the fiber on a detector, and measuring the location of the image of the center of the core relative to the location of the image of the center of the cladding in the first angular position. The fiber segment is then rotated about the axis of rotation to a second angular position and the location of the image of the center of the core relative to the location of the image of the center of the cladding in the second angular position is measured. The fiber segment is again rotated about the axis of rotation to a third angular position and the location of the image of the center of the core relative to the image of the center of the cladding in the third angular position is measured.

Abstract: An optical test instrument, for testing response of an optical medium to optical energy, comprises a light source for emitting optical energy in response to electrical energy, a detector for providing an electrical output signal in response to incident optical energy, and a propagation path for delivering optical energy from the light source to the medium under test and for delivering optical energy from the medium under test to the detector. A positioning mechanism displaces an optical attenuator element between a first position, in which it is out of the propagation path, and a second position, in which it is interposed in a segment of the path in which the optical energy is propagated as a beam.

Abstract: An optical multiplexer comprises a signal energy divider, such as a directional coupler, for dividing optical signal energy received by way of a multiplexer upstream port into a control portion and a utilization portion, and an optical switch having a first switch port connected to receive the utilization portion of the optical signal energy and having a plurality of additional switch ports connected to repsecive multiplexer downstream ports. A decoder extracts a control message from the control portion of the optical signal energy, and a controller is responsive to the control message for selectively setting the switch to interconnect the first switch port and a selected one of the additional switch ports. In this manner, at least part of the utilization portion of the optical signal energy received by the multiplexer by way of the multiplexer upstream port is emitted from the multiplexer by way of the multiplexer downstream port that is connected to the selected one of the additional switch ports.

Abstract: A method of aligning first and second substantially parallel rod-form elements, such as optical fibers, comprises placing the first element at a position at which it is approximately aligned with the second element and is in the fields of view of two imaging systems that have respective axes that are oblique to each other and to the central axes of the two rod-form elements, and digitizing at least a part of the image of each field of view. The digital data is analyzed to determine location of the first element in each field of view, and relative displacement of the first and second elements is brought about accordingly.

Abstract: A method of testing a length section of optical fiber in order to determine whether the angle between an end face of the length section and a plane perpendicular to a longitudinal axis of the length section of optical fiber is within a predetermined range, comprises positioning the length section of optical fiber so that its longitudinal axis substantially coincides with the optical axis of a camera, selecting at least two test regions on the end face of the fiber, adjusting the position of at least one of a camera, a lens and the length section of optical fiber to focus each of the test regions on the sensing surface of the camera, and comparing the adjustments performed in the preceding step for the two test regions respectively.