Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Observation of soliton pulse compression in photonic crystal waveguides   We demonstrate soliton-effect pulse compression in mm-long photonic crystal
waveguides resulting from strong anomalous dispersion and self-phase
modulation. Compression from 3ps to 580fs, at low pulse energies(~10pJ), is
measured via autocorrelation.

31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
34
The categories of this paper are: chem-ph
4
The categories of this paper are: cond-mat
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg