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Date of Conference: 16-21 May 2010 Conference Name: Conference on Lasers and Electro-Optics, CLEO-QELS 2010 Repetition-frequency stabilization of a Yb-doped fiber laser to the Cesium standard is reported. Laser amplitude and phase noise is characterized. Performance is limited to 2x10-14 at 100000 averaging time by intrinsic stability of the Cs-standard.

We present a frequency stabilized laser at 2051 nm based on a versatile all-fibered stabilization setup. A modulation sideband locking technique is implemented to lock the laser at a controlled frequency detuning from the center of the CO2 R(30) transition envisaged for space-borne differential absorption lidar (DIAL) applications. This method relies on the use of a compact all-fibered gas reference cell that makes the setup robust and immune to mechanically induced optical misalignments. The gas cell is fabricated using a hollow-core photonic crystal fiber filled with pure CO2 at a low pressure of ~20 mbar and hermetically sealed at both ends by splices to silica fibers. Different configurations of this fibered cell have been developed and are presented. With this technique, frequency stabilities below 40 kHz at 1-s integration time and

Space interferometers consisting of several free flying telescopes, such as the planned Darwin mission, require a complex metrology system to make all the components operate as a single instrument. This metrology system consists of various sub-systems to monitor distances, angles and speeds. Our research focuses on one of these sub-systems that measures the absolute distance between two satellites with high accuracy. For Darwin the required accuracy would be in the order of 10 μm over 250 meter. To measure this absolute distance, we are currently building a frequency sweeping interferometer. It is operated by first measuring a phase in the interferometer, sweeping a tunable laser over a known frequency interval and finally measuring a second phase. By also counting the number of fringes during the sweep it is possible to determine the absolute path length difference without ambiguities. We plan on actively stabilizing the wavelength at the endpoints of the sweep on a Fabry-Perot cavity using the Pound-Drever-Hall technique. In this way the unknown distance is directly referenced to the length of the Fabry-Perot cavity.

A self-starting, passively stabilized, monolithic all-polarization- maintaining femtosecond Yb-fiber master oscillator / power amplifier with very high operational and environmental stability is demonstrated. The system is based on the use of two different photonic crystal fibers. One is used in the oscillator cavity for dispersion balancing and nonlinear optical limiting, and another one is used for low-nonlinearity final pulse recompression. The chirped-pulse amplification and recompression of the 232-fs, 45-pJ/pulse oscillator output yields a final direct fiber-end delivery of 7.3-nJ energy pulses of around 297 fs duration. Our laser shows exceptional stability. No Q-switched modelocking events were detected during 4-days long observation. An average fluctuation of only 7.85 x 10(-4) over the mean output power was determined as a result of more than 6-hours long measurement. The laser is stable towards mechanical disturbances, and maintains stable modelocking in the temperature range of at least 10 - 40 (0)C.