US 4,309,105 AGranted

Method and apparatus for testing performance of fiber optic cable components and assemblies

AssigneeThe United States of America as represented by the Secretary of the Navy

InventorRobert L. Lebduska

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Abstract

Optical performance characteristics of fiber optical cable components and assemblies are tested for quality in an accurate, consistent, and stable manner by the method and apparatus of this invention. The novel apparatus enables acceptability testing of a supplier's fiber optic component/assembly by comparing its optical transmission level with the level of a similar known acceptance cable or a calibration cable, the latter two cables being incorporated in the invention apparatus. Other optical parameters can be tested by this invention to determine additional line losses, such as insertion losses, optical continuity, signal modulation, etc. Stability in the test method is assured by utilizing a variable, calibrated power source. The accurateness of the method is achieved by simultaneously coupling light from a common optical source into both the invention apparatus cables and the fiber optic cable component/assembly to be tested, which arrangement eliminates amplitude drift of the optical source and of the apparatus detector from affecting the validity of subsequent relative measurements of the optical outputs.

Claims4

Dependent claims

An apparatus for the long term, continuous testing of the optical performance characteristics of a fiber optic cable assembly having a pair of input and output fiber optic cables each having end terminations and of known physical characteristics comprising:

a radiant energy source mounted on a chassis;
a pair of optical output terminals oriented to receive and pass radiant energy therethrough;
a single optical detector mounted on the chassis;
a pair of optical input terminals oriented to receive and pass radiant energy to the detector being mounted on the chassis;
a light chopper interposed between the optical input terminals and the detector to selectively permit radiant energy from one optical terminal or the other to the detector;
a standardization cable having the same optical and physical characteristics as the input and output cables, said standardization cable having optically acceptable end terminations coupled between one optical output terminal and one optical input terminal, the other optical output terminal and the other optical input terminal having the fiber optic cable assembly coupled therebetween;
and
means coupled to the single optical detector for comparing the respective output radiant power levels of the fiber optic cable assembly and the standardization cable assembly when each are connected between a respective pair of output and input terminals.

5 more elements

Dependencies are inferred from the claim text.