INTERNATIONAL COMPARISON OF STABILIZED HE-NE LASERS BY THE SATURATED ABSORPTION OF I-127(2) AT LAMBDA-APPROXIMATE-TO-633 NM INVOLVING THE CEM (SPAIN), THE IPQ (PORTUGAL) AND THE BIPM
E. Prieto et al., INTERNATIONAL COMPARISON OF STABILIZED HE-NE LASERS BY THE SATURATED ABSORPTION OF I-127(2) AT LAMBDA-APPROXIMATE-TO-633 NM INVOLVING THE CEM (SPAIN), THE IPQ (PORTUGAL) AND THE BIPM, Metrologia, 32(5), 1996, pp. 379-384
The results of an international comparison of iodine-stabilized He-Ne
lasers at lambda approximate to 633 nm, made by beat-frequency techniq
ues, between the CEM (Spain), the IPQ (Portugal) and the BIPM are pres
ented. Four lasers took part in the ten-day period of measurements, an
d were compared once or twice a day. The frequency differences between
the lasers were all less than 6 kHz and the highest standard uncertai
nty of the mean of the frequency differences between two lasers was 7
kHz. These results lie inside the standard uncertainty given in the mi
se en pratique of the definition of the metre. Parameters which affect
the frequency of the lasers, such as modulation width, iodine pressur
e and laser power, were also investigated.