Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Micro-resonator soliton generated directly with a diode laser   An external-cavity diode laser is reported with ultralow noise, high power
coupled to a fiber, and fast tunability. These characteristics enable the
generation of an optical frequency comb in a silica micro-resonator with a
single-soliton state. Neither an optical modulator nor an amplifier was used in
the experiment. This demonstration greatly simplifies the soliton generation
setup and represents a significant step forward to a fully integrated soliton
comb system.

25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg
6
The categories of this paper are: astro-ph
8
The categories of this paper are: hep-ex
32
The categories of this paper are: atom-ph
15
The categories of this paper are: nucl-ex
27
The categories of this paper are: comp-gas
18
The categories of this paper are: econ
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess