Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Low power, chip-based stimulated Brillouin scattering microwave photonic
  filter with ultrahigh selectivity   Highly selective and reconfigurable microwave filters are of great importance
in radio-frequency signal processing. Microwave photonic (MWP) filters are of
particular interest, as they offer flexible reconfiguration and an order of
magnitude higher frequency tuning range than electronic filters. However, all
MWP filters to date have been limited by trade-offs between key parameters such
as tuning range, resolution, and suppression. This problem is exacerbated in
the case of integrated MWP filters, blocking the path to compact, high
performance filters. Here we show the first chip-based MWP band-stop filter
with ultra-high suppression, high resolution in the MHz range, and 0-30 GHz
frequency tuning. This record performance was achieved using an ultra-low
Brillouin gain from a compact photonic chip and a novel approach of optical
resonance-assisted RF signal cancellation. The results point to new ways of
creating energy-efficient and reconfigurable integrated MWP signal processors
for wireless communications and defence applications.

9
The categories of this paper are: nlin
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
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The categories of this paper are: q-fin
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The categories of this paper are: econ
26
The categories of this paper are: bayes-an
2
The categories of this paper are: math
29
The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th