Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Photonic Generation of Radar Signals with 30 GHz Bandwidth and
  Ultra-High Time-Frequency Linearity   Photonic generation of radio-frequency signals has shown significant
advantages over the electronic counterparts, allowing the high precision
generation of radio-frequency carriers up to the terahertz-wave region with
flexible bandwidth for radar applications. Great progress has been made in
photonics-based radio-frequency waveform generation. However, the approaches
that rely on sophisticated benchtop digital microwave components, such as
synthesizers and digital-to-analog converters have limited achievable bandwidth
and thus resolution for radar detections. Methods based on voltage-controlled
analog oscillators exhibit high time-frequency non-linearity, causing degraded
sensing precision. Here, we demonstrate, for the first time, a photonic
stepped-frequency (SF) waveform generation scheme enabled by MHz electronics
with a tunable bandwidth exceeding 30 GHz and intrinsic time-frequency
linearity. The ultra-wideband radio-frequency signal generation is enabled by
using a polarization-stabilized optical cavity to suppress intra-cavity
polarization-dependent instability; meanwhile, the signal's high-linearity is
achieved via consecutive MHz acousto-optic frequency-shifting modulation
without the necessity of using electro-optic modulators that have bias-drifting
issues. We systematically evaluate the system's signal quality and imaging
performance in comparison with conventional photonic radar schemes that use
high-speed digital electronics, confirming its feasibility and excellent
performance for high-resolution radar applications.

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The categories of this paper are: plasm-ph
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The categories of this paper are: chao-dyn
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The categories of this paper are: econ
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The categories of this paper are: nucl-ex
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The categories of this paper are: astro-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: quant-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: stat
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The categories of this paper are: math
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The categories of this paper are: nucl-th
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The categories of this paper are: q-bio