Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On-chip ultra-narrow-linewidth single-mode microlaser on lithium niobate
  on insulator   We report an on-chip single mode microlaser with low-threshold fabricated on
Erbium doped lithium niobate on insulator (LNOI). The single mode laser
emission at 1550.5 nm wavelength is generated in a coupled photonic molecule,
which is facilitated by Vernier effect when pumping the photonic molecule at
970 nm. A threshold pump power as low as 200 uW is demonstrated thanks to the
high quality factor above 10^6. Moreover, the linewidth of the microlaser
reaches 4 kHz, which is the best result in LNOI microlasers. Such single mode
micro-laser lithographically fabricated on chip is highly in demand by photonic
community.

37
The categories of this paper are: supr-con
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
15
The categories of this paper are: nucl-ex
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
1
The categories of this paper are: cs
34
The categories of this paper are: chem-ph
17
The categories of this paper are: q-fin
22
The categories of this paper are: chao-dyn
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
33
The categories of this paper are: plasm-ph
4
The categories of this paper are: cond-mat