NIST technology helps ensure reliability of military communications

The Army, Navy and Air Force use thousands of miles of optical fibers on ships, planes and land-based installations to transmit voice and data. They needed a simple, effective and highly accurate way to measure the amount of light delivered by these glass "wires" at key points in the transmission system. Power degradation along the network can cause communication failure.

Working with ILX Lightwave Corp. of Bozeman, Mont., the National Institute of Standards and Technology (NIST) came up with a system capable of world-class optical measurements with push-button convenience. The system consists of a NIST-designed optical detector and an optical multimeter--designed by ILX Lightwave--that measures light emitted from a fiber over a wide range of wavelengths. There are two versions of the novel detector--one using silicon-based sensors and the other using germanium-based sensors. The sensors connect directly to an optical fiber without any additional optics and with barely measurable light loss.

Measurement uncertainty is half that of previous optical fiber power detectors.

The system is described in an upcoming issue of the journal Metrologia.

According to NIST engineer John Lehman, independent measurements of the detector's performance by NIST and its German counterpart, PTB (Physikalisch-Technische Bundesanstalt), are in "excellent agreement." Another comparison will be made this summer with NIST's British counterpart, the National Physical Laboratory.

The new systems are now being shipped to military calibration centers where they will be used to annually check the accuracy of optical fiber power systems utilized in the field.

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