Lucent Technologies Inc.

Fitel USA Corporation

The Furukawa Electric Co., Ltd.

Lego A/s

Flemming Pedersen

Nobuaki Orita

Christian Jakobsen

Tracy E Brewer

Leonardo M Penn

Aarne Karp

David H Smithgall, Sr

David Harry Smithgall

Alex Bojstrup

Jens Stamp LAMBÆK

Peter Hasloev

The present invention provides a method and an apparatus for measuring the diameter and/or eccentricity of the one or more coating layers of a coated optical fiber. The present invention preferably is utilized to measure the diameter of the primary coating layer of a coated optical fiber after the primary and secondary coating layers have been applied to the optical fiber. The primary coating layer is disposed about the optical fiber and the secondary coating layer is disposed about the primary coating layer. When a beam of light is projected by a light source through the optical fiber in a direction substantially perpendicular to the axial direction of the optical fiber, an image is formed on an optical detector, which is disposed opposite the light source and substantially perpendicular to the axial direction of the optical fiber. The light passing through the coated optical fiber is focused by a lens onto the optical detector. The lens is coaxially aligned with the beam of light projected by the light source. The image is analyzed by a signal processor to determine the diameter and/or eccentricity of the primary coating layer of the coated optical fiber. The image generated by the optical detector includes first and second bright lines at the interfaces of the primary and secondary coating layers. The relative locations of one or both of these bright lines in the image are utilized to determine the diameter and/or eccentricity of the primary coating layer.

Method and apparatus for measuring the diameter and/or eccentricity of a coating layer of a coated optical fiber

The present invention provides an optical detection system for detecting defects in an optical fiber. The system comprises a light source for projecting a beam of light onto the coating layer of an optical fiber. An optical detector positioned adjacent the optical fiber receives a first light ray reflected at the interface of the air and the coating layer as the light enters the coating layer surrounding the optical fiber and a second light ray reflected at the interface of the air and the coating layer as the light exits the coating layer after passing through the optical fiber. When a defect, such as an airline, for example, is present in the optical fiber, a third light ray is reflected by the defect and is detected by the optical detector. A signal processor is electrically coupled to the optical detector for receiving an output signal from the optical detector and for processing the output signal to determine whether or not one or more defects have been detected. In accordance with the preferred embodiment, when only two rays of light are detected, the signal processor determines that no defects exist in the optical fiber. When three rays of light are detected, the signal processor determines that a defect exists in the optical fiber.

Method and apparatus for detecting defects in an optical fiber

The present invention provides an optical detection system for detecting defects in an optical fiber. The system includes a light source for coupling light into the secondary coating of an optical fiber at a preselected angle with respect to the longitudinal axis of the fiber and an optical detector positioned adjacent the fiber at a preselected distance from the point at which the light is coupled into the fiber coating. In accordance with one embodiment, the light is coupled into the fiber coating at a sufficiently shallow angle with respect to the longitudinal axis of the fiber to cause the light to travel through the coating in a direction substantially parallel to the axis of the optical fiber for some distance before exiting the coating. By placing the detector a preselected distance from the coupling point, detection of light reflected from the fiber at the coupling spot is avoided and only light reflected by defects contained in the primary or secondary coating layers, or light reflected by delaminations between the primary coating layer and the fiber, will be detected by the detector.

Method and apparatus for distinguishing between defects in an optical

Method and apparatus for detecting defects in an optical fiber coating

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Farum, Denmark

Flemming Pedersen