286 research outputs found
8E-17 fractional laser frequency instability with a long room-temperature cavity
We present a laser system based on a 48 cm long optical glass resonator. The
large size requires a sophisticated thermal control and optimized mounting
design. A self balancing mounting was essential to reliably reach sensitivities
to acceleration of below < 2E-10 /g in all directions.
Furthermore, fiber noise cancellations from a common reference point near the
laser diode to the cavity mirror and to additional user points (Sr clock and
frequency comb) are implemented. Through comparison to other cavity-stabilized
lasers and to a strontium lattice clock an instability of below 1E-16 at
averaging times from 1 s to 1000 s is revealed
Die Wahrnehmung der europäischen ‚historischen Moderne’ in Zeitschriften und anderen Stellungnahmen der deutschen Sozialdemokratie zwischen 1890 und 1910
Characterization of a 450-km Baseline GPS Carrier-Phase Link using an Optical Fiber Link
A GPS carrier-phase frequency transfer link along a baseline of 450 km has
been established and is characterized by comparing it to a phase-stabilized
optical fiber link of 920 km length, established between the two endpoints, the
Max-Planck-Institut f\"ur Quantenoptik in Garching and the
Physikalisch-Technische Bundesanstalt in Braunschweig. The characterization is
accomplished by comparing two active hydrogen masers operated at both
institutes. The masers serve as local oscillators and cancel out when the
double differences are calculated, such that they do not constitute a
limitation for the GPS link characterization. We achieve a frequency
instability of 3 x 10^(-13) in 30 s and 5 x 10^(-16) for long averaging times.
Frequency comparison results obtained via both links show no deviation larger
than the statistical uncertainty of 6 x 10^(-16). These results can be
interpreted as a successful cross-check of the measurement uncertainty of a
truly remote end fiber link.Comment: 14 pages, 6 figure
Analysis of the National Environmental Policy Act of 1969 and of Environmental Impact Matrices
Bioenvironmental Engineerin
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