Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Ultra-stable optical frequency dissemination on a multi-access fibre
  network   We report the dissemination of an ultrastable optical frequency signal to two
distant users simultaneously using a branching network. The ultrastable signal
is extracted along a main fibre link; it is optically tracked with a
narrow-linewidth laser diode, which light is injected in a secondary link. The
propagation noise of both links is actively compensated. We implement this
scheme with two links of 50-km fibre spools, the extraction being setup at the
mid-point of the main link. We show that the extracted signal at the end of the
secondary link exhibits fractional frequency instability of 1.4x10-15 at 1-s
measurement time, almost equal to the 1.3x10-15 instability of the main link
output end. The long-term instabilities are also very similar, at a level of
3-5x10-20 at 3x104-s integration time. We also show that the setting up of this
extraction device, or a simpler one, at the main link input, can test the
proper functioning of the noise rejection on this main link. This work is a
significant step towards a robust and flexible ultra-stable network for
multi-users dissemination.

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The categories of this paper are: cond-mat
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The categories of this paper are: astro-ph
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The categories of this paper are: q-bio
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The categories of this paper are: stat
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The categories of this paper are: hep-th
23
The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: bayes-an
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: chem-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: econ