December, 2001

EEEL Develops New High-Accuracy Transfer Standards for Optical-Fiber Power Metrology

John Lehman of EEEL's Optoelectronics Division has developed a new transfer standard that will enable higher accuracy calibrations of optical fiber power meters, one of the Division's fastest growing measurement services.

Because they accept laser radiation through an optical fiber connector, optical fiber power meters cannot be calibrated directly against the appropriate primary standard—in this case, the Laser-Optimized Cryogenic Radiometer (LOCR). Instead, a customer's instrument is calibrated against a specially designed transfer standard, which is suitable for calibration with a collimated beam and use with the highly divergent light from an optical fiber. It must have a very large field of view and low sensitivity to polarization, as well as being spatially uniform and stable.

Lehman's design builds upon earlier, multiple reflection, trap designs, modified to achieve a field of view of up to 30 degrees. It can be constructed with either silicon or germanium detectors, to provide spectral coverage from 450 nm to 1800 nm.

Along with the new transfer standard, a new field-of-view measurement system, based on an industrial 6-axis robot, was developed to characterize this and other optical detectors. The work was funded by the DoD Calibration Coordination Group, and copies of the new transfer standards will be supplied to DoD metrology laboratories.

Contact:

Paul D. Hale, (303) 497-5367