Absolute frequency measurement of wavelength standard at 1542nm: acetylene stabilized DFB laser.

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.

Long term comparison of two fiber based frequency comb systems.

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.

Quasi-continuous-wave birefringence-compensated single- and double-rod Nd:YAG lasers.

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.