High Power Fibre Optic Calibration

Three Nordic National Metrology Institutes (NMIs) and one company participated in the Nordtest project no 1634-03 High Power Fibre Optic Calibration. The project was successful and the service of calibrating high power fibre optic detectors can now be offered by the three NMIs. Each of the NMIs has established traceability to their own national standards for optical power. The NMIs used the same method for generating high power by using a medium power diode laser that in turn was amplified by an Erbium Doped Fibre Amplifier. A comparison of fibre optic power measurements in the power range from 1 mW up to 200 mW was made in October 2003 at the HUT Metrology Research Institute. Fibre optic power was compared at 1 mW level using low power detectors calibrated at an uncertainty level of 0,75% 1,5 % (k=2). Results show deviations from average within the respective measurement uncertainties. Linearity was tested for three high power detectors, one from each laboratory, in the range from 5 mW to 200 mW. All three detectors were linear within 1 % over the whole range. The high power detector comparison was performed in the power range from 5 mW to 200 mW. Four detectors were compared. Results show that the largest deviation from the mean is 1,4 % well within the measurement uncertainty of the respective laboratory. Uncertainty for the high power detector at power levels from 5 mW and up to 200 mW is estimated to lie between 1,3 and 3 % for the three laboratories, respectively. Based on the experience gained, the participants produced a Nordtest Method that describes measurement procedures that can be used to calibrate fibre optic power meters up to 200 mW power levels.