Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Down-conversion source of positively spectrally correlated and
  decorrelated photon pairs at telecom wavelength   The frequency correlation (or decorrelation) of photon pairs is of great
importance in long-range quantum communications and photonic quantum computing.
We experimentally characterize a spontaneous parametric down conversion (SPDC)
source, based on a Beta-Barium Borate (BBO) crystal cut for type-II phase
matching at 1550 nm which emits photons with the positive or no spectral
correlations. Our system employs a carefully designed detection method
exploiting two InGaAs detectors.

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The categories of this paper are: atom-ph
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The categories of this paper are: funct-an
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The categories of this paper are: solv-int
2
The categories of this paper are: math
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The categories of this paper are: astro-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom
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The categories of this paper are: patt-sol
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The categories of this paper are: comp-gas
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The categories of this paper are: cmp-lg
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The categories of this paper are: hep-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: q-fin
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The categories of this paper are: stat