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A compact and simplified 13C2H2 optical frequency standard is currently under development at NPL. The standard uses an inexpensive, commercially available 20 mW DFB diode laser, which is stabilized to line P(16) of the nu1 + nu3 band at 1542 nm in an experimental arrangement which dispenses with the need for an enhancement cavity. Preliminary stability and reproducibility data will be presented.
We describe the recent advances of the NRC single ion based optical frequency standard using the 445-THz S-D transition in 88Sr+. Laser cooled confinement and probing of the clock transition has been obtained for periods exceeding 24 hours showing high levels of stability. Spectral resolutions better than 5 Hz at 445 THz have been obtained. Work is described on the development of an improved ion trap...
We present an optical frequency comb generator (OFCG) based on a fiber ring laser that provides a bandwidth of over 700 GHz with modeless operation. The OFCG was developed via a configuration with frequency shifted feedback fiber ring laser utilizing an acousto-optic modulator (AOM) with a carrier frequency of 150 MHz when acetylene stabilized laser was injected into the fiber ring cavity as a seeding...
Both SI units, the candela and the kelvin were originally derived from standard blackbody sources. Recently, instead of source-based calibrations, they both have been realized with optical detector standards. Recent decrease of the measurement uncertainties in detector-based calibrations resulted in improved uncertainties in these SI units.
Two 674-nm optical frequency standards based on the 2S1/2 - 2D5/2 transition in 88Sr+ are under development at NPL. Comparison of the standards allows determination of the frequency stability and reproducibility via difference frequency measurements. A relative frequency stability between the traps of ap3times10-15 over a 100 s averaging time has been observed. A compact, transportable system is also...
Optical fiber power meter (OFPM) linearity standards of NMIJ (Japan) and NIST (USA) are compared using a commercial OFPM as a transfer standard at 1310 nm and 1550 nm over a power range [-60 dBm, 0 dBm]. At both wavelengths the comparison indicates an agreement between the two laboratories within the combined uncertainty. At 1550 nm the uncertainties are larger, which is attributed to unstable operation...
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