Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: 1.5um Polarization-Entangled Bell States Generation Based on
  Birefringence in High Nonlinear Microstructure Fiber   Polarization-entangled photon pair generation based on two scalar scattering
processes of the vector four photon scattering has been demonstrated
experimentally in high nonlinear microstructure fiber with birefringence. By
controlling the pump polarization state, polarization-entangled Bell states can
be realized. It is provides a simple way to realize efficient and compact fiber
based polarization-entangled photon pair sources.

22
The categories of this paper are: chao-dyn
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
18
The categories of this paper are: econ
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph
27
The categories of this paper are: comp-gas