Absolute frequency measurement of the 435.5 nm 171 Yb + clock transition with a Kerr-lens mode-locked femtosecond laser

No abstract

We report on nearly quantum-limited timing-jitter performance of two passively mode-locked Er:Yb:glass lasers with a repetition rate of 10 GHz. The relative timing jitter of both lasers was measured to be 190 fs (100 Hz-1.56 MHz) root mean square. The remaining cavity-length fluctuations are below 7.5 pm in the 6 Hz-8 kHz frequency range, indicating the stability of a rugged miniature cavity setup. By actively controlling the cavity length we reduced the timing jitter to 26 fs (6 Hz-1.56 MHz). We also discuss the influence of cavity length on the practically achievable timing jitter.

We present a sub-85 fs self-starting stretched-pulse passively mode-locked Erbium-fiber oscillator in a sigma setup with tunable repetition rate. The sigma cavity included a movable mirror enabling a tunable pulse repetition rate variation of +/- 1 % from 55.3 MHz to 56.4 MHz with continuous, uninterrupted mode-locked operation and an output power around 14 mW. Based on the wide tuning range of the repetition rate the presented fiber oscillator is a suitable candidate for applications in femtosecond spectroscopy or precision metrology around 1.56 microm.

We report on the measurement of an Erbium-fiber oscillator's carrier-envelope-offset frequency using an extruded SF6 photonic crystal fiber for the generation of a more than two octave-spanning supercontinuum from 400 nm to beyond 1750 nm. A modified type of f-2f-interferometer was employed, beating the frequency doubled input signal of the fiber oscillator with the supercontinuum to generate the carrier-envelope-offset beat. Controlling the fiber oscillator's pump power with an electronic feedback loop, we phase-locked the carrier-envelope-offset frequency to an external reference source. The resulting residual phase excursions correspond to fractional frequency instabilities of the oscillator's frequency comb of the order of 10(-16) for averaging times longer than 10 s.