Cryogenic Primary Standard for Optical Fiber Power Measurement

NIST has completed commissioning a new, state-of-the-art cryogenic primary standard for optical fiber power measurement and calibration. It establishes for the first time, a direct traceability route between the device under test and primary standard. A silicon micro-machined planar detector, incorporating a carbon nanotube absorber and superconducting transition edge temperature sensor, forms the basis of the radiometer, whilst advanced thermal filtering ensures noise-free operation. Measurement repeatability below 50ppm is routinely achieved. The measurement uncertainty (k=\pmb2) is 0.40
^%
, a 20% improvement on NIST's previous capability. The new primary standard benefits the telecommunications industry.