Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Post-selection free, integrated optical source of non-degenerate,
  polarization entangled photon pairs   We present an integrated source of polarization entangled photon pairs in the
telecom regime, which is based on type II-phasematched parametric
down-conversion (PDC) in a Ti-indiffused waveguide in periodically poled
lithium niobate. The domain grating -- consisting of an interlaced bi-periodic
structure -- is engineered to provide simultaneous phase-matching of two PDC
processes, and enables the direct generation of non-degenerate, polarization
entangled photon pairs with a brightness of $B=7\times10^3$ pairs/(s mW GHz).
The spatial separation of the photon pairs is accomplished by a fiber-optical
multiplexer facilitating a high compactness of the overall source. Visibilities
exceeding 95% and a violation of the Bell inequality with $S=2.57\pm0.06$ could
be demonstrated.

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The categories of this paper are: math-ph
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The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
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The categories of this paper are: nucl-ex
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: q-fin
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: adap-org