Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An on-chip astrophotonic spectrograph with a resolving power of 12,000   With the upcoming extremely large telescopes (ELTs), the volume, mass, and
cost of the associated spectrographs will scale with the telescope diameter.
Astrophotonics offers a unique solution to this problem in the form of
single-mode fiber-fed diffraction-limited spectrographs on a chip. These highly
miniaturized chips offer great flexibility in terms of coherent manipulation of
photons. Such photonic spectrographs are well-suited to disperse the light from
directly imaged planets (post-coronagraph, collected using a single-mode fiber)
to characterize exoplanet atmospheres. Here we present the results from a
proof-of-concept high-resolution astrophotonic spectrograph using the arrayed
waveguide gratings (AWG) architecture. This chip uses the low-loss SiN platform
(SiN core, SiO$_2$ cladding) with square waveguides (800 nm $\times$ 800 nm).
The AWG has a measured resolving power ($\lambda/\delta\lambda$) of $\sim$
12,000 and a free spectral range (FSR) of 2.8 nm. While the FSR is small, the
chip operates over a broad band (1200 $-$ 1700 nm). The peak on-chip throughput
(excluding the coupling efficiency) is $\sim$40\% (- 4 dB) and the overall
throughput (including the coupling loss) is $\sim$ 11\% (- 9.6 dB) in the TE
mode. Thanks to the high-confinement waveguide geometry, the chip is highly
miniaturized with a size of only 7.4 mm $\times$ 2 mm.
  This demonstration highlights the utility of SiN platform for astrophotonics,
particularly, the capability of commercial SiN foundries to fabricate
ultra-small, high-resolution, high-throughput AWG spectrographs on a chip
suitable for both ground- and space-based telescopes.

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The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
0
The categories of this paper are: hep-ph
32
The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: patt-sol
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The categories of this paper are: hep-ex
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The categories of this paper are: quant-ph
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The categories of this paper are: supr-con
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The categories of this paper are: cs
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The categories of this paper are: funct-an
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The categories of this paper are: chao-dyn
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The categories of this paper are: cond-mat
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The categories of this paper are: nucl-ex
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat