NIST researchers complete international intercomparison of optical fiberpower measurements. (General Developments).

NIST researchers recently completed an international intercomparison of optical fiber power measurements with researchers from Physikalisch-Technische Bundesanstalt (PTB). This work, which has been submitted to Metrologia, is part of an ongoing effort to reduce the overall uncertainty of laser and optical fiber power meter (OFPM) calibrations.

This past summer, a novel NIST transfer standard based on germanium photodiodes was used in an intercomparison of OFPMs with PTB at nominal wavelengths of 1300 nm and 1550 nm (wavelengths at which most of the world's optical-fiber-based communication is transmitted). Measurement results showed differences of less than 1.5 x [10.sup.3]--well within the combined uncertainty for both laboratories--demonstrating that optical fiber power measurements from the laboratories are among the best in the world. The NIST transfer standard, developed as part of an ongoing effort to provide lower uncertainty for OFPM calibrations, has a coupling efficiency very near unity up to a numerical aperture (NA) of 0.26. This is very important for applications such as optical fiber where the light incident on the detector has a large angular divergence. The transfer standard can be calibrated directly against a primary standard with collimated radiation as well as being used to accurately measure optical power from a fiber, without intervening optics.

CONTACT: Igor Vayshenker, [phone]; igor. [e-mail]. or John Lehman, [phone]; [e-mail].