Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Enhanced transmission capacity for laser communication at the
  single-photon level using the multi-channel frequency coding scheme   The statistical properties of a radiation sources are commonly characterized
by second-order-correlation or Mandel parameter. Our research found that the
single photons modulation spectrum provides us another optional way which is
more sensitive to the high frequency information contained in the photon
sequence. In this paper, we present direct laser communication by using a
multi-channel frequency coding scheme based on the single photons modulation
spectrum in which the multi-frequency modulation makes the transmission
capacity efficiently enhanced. The modulation frequencies could be operated in
a wide band without frequency aliasing due to the inherent randomness of
photons arrival time of weak coherent light. The error rate less than 10-5 has
been achieved experimentally when the mean signal photon count is 80 kcps. The
modulated coherent light field shows nonlinear effects of single photons
modulation spectrum. The studies of statistical properties of the single
photons modulation spectrum, including the dependence of mean noise photon
count, integration time, channel spacing and the number of frequency component,
helped us to optimize the error rate and transmission capacity.

14
The categories of this paper are: math-ph
21
The categories of this paper are: adap-org
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
32
The categories of this paper are: atom-ph
1
The categories of this paper are: cs
19
The categories of this paper are: eess
36
The categories of this paper are: cmp-lg
12
The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat