Mode-locked erbium-doped fiber lasers are ideal comb generators for optical frequency metrology. We compare two fiber frequency combs by measuring an optical frequency independently with both combs and comparing their results. The two frequency measurements agree within 6x10-16. This is to our knowledge the first direct comparison between two fiber based frequency combs.
The frequency of a wavelength standard at 1542 nm (194 THz) developed in CMI for the telecommunication band C was measured with a fiber femtosecond frequency comb. The measurement was done for three transitions of acety(13)C(2)H(2): P(14), P(15) and P(16). The results agree well with values in the recommendation for Practical realization of the definition of the metre [1] and even better with recent measurements made in NMIJ/AIST [2,3] - the differences are lower than 2 kHz (or 1x10-(-11) rel.) for all three transitions. This agreement is significant considering the fact that the CMI laser uses an extremely simple spectroscopic arrangement and substantially lower saturation power.
Compensation of thermally induced birefringence directed toward compensation of depolarization and bifocusing in laser rods is treated with simple beam transfer matrices. When we apply a 90-deg polarization-rotating element to a resonator, the radial and the tangential eigensolutions of the resonator change significantly. The effect of this alteration on the resonator's stability is investigated in detail. The outcome is used to design a single- and double-rod resonator resulting in 53 W with an M2 approximately 1.5 and 182 W of output power with an M2 approximately 1.2, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.