Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Free Space Optical Polarization De-multiplexing and Multiplexing by
  means of Conical Refraction   Polarization de-multiplexing and multiplexing by means of conical refraction
is proposed to increase the channel capacity for free space optical
communication applications. The proposed technique is based on the
forward-backward optical transform occurring when a light beam propagates
consecutively along the optic axes of two identical biaxial crystals with
opposite orientations of their conical refraction characteristic vectors. We
present experimental proof of usefulness of the conical refraction
de-multiplexing and multiplexing technique by increasing in one order of
magnitude the channel capacity at optical frequencies in a propagation distance
of 4m.

33
The categories of this paper are: plasm-ph
18
The categories of this paper are: econ
1
The categories of this paper are: cs
15
The categories of this paper are: nucl-ex
21
The categories of this paper are: adap-org
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
30
The categories of this paper are: q-alg
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph