Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Thermal phase shifters for femtosecond laser written photonic integrated
  circuits
30
The categories of this paper are: q-alg
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
26
The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph
31
The categories of this paper are: ao-sci
33
The categories of this paper are: plasm-ph
5
The categories of this paper are: gr-qc
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess