Round robin for optical fiber Bragg grating metrology

NIST has administered the first round robin of measurements for optical fib er Bragg gratings. We compared the measurement of center wavelength, bandwi dth, isolation, minimum relative transmittance, and relative group delay am ong several grating types in two industry groups, telecommunications and se nsors. We found that the state of fiber Bragg grating metrology needs impro vement in most areas. Specifically, when tunable losers ave used a filter i s needed to remove broadband emissions from the laser. The linear slope of relative group delay measurements is sensitive to drift and systematic bias in the rf-modulation technique. The center wavelength measurement had a ra nge of about 27 pm in the sensors group and is not adequate to support long -term structural monitoring applications.