Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Arbitrary coupling ratio multimode interference couplers in
  Silicon-on-Insulator   In this paper we present the design, manufacturing, characterization and
analysis of the coupling ratio spectral response for Multimode Interference
(MMI) couplers in Silicon-on-Insulator (SOI) technology. The couplers were
designed using a Si rib waveguide with SiO 2 cladding, on a regular 220 nm film
and 2 {\mu}m buried oxide SOI wafer. A set of eight different designs, three
canonical and five using a widened/narrowed coupler body, have been subject of
study, with coupling ratios 50:50, 85:15 and 72:28 for the former, and 95:05,
85:15, 75:25, 65:35 and 55:45 for the latter. Two wafers of devices were
fabricated, using two different etch depths for the rib waveguides. A set of
six dies, three per wafer, whose line metrology matched the design, were
retained for characterization. The coupling ratios obtained in the experimental
results match, with little deviations, the design targets for a wavelength
range between 1525 and 1575 nm, as inferred from spectral measurements and
statistical analyses. Excess loss for all the devices is conservatively
estimated to be less than approximately 2 dB. All the design parameters, body
width and length, input/output positions and widths, and tapers dimensions are
disclosed for reference.

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The categories of this paper are: q-alg
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The categories of this paper are: acc-phys
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The categories of this paper are: math-ph
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The categories of this paper are: solv-int
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The categories of this paper are: hep-th
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The categories of this paper are: adap-org
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The categories of this paper are: q-fin
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The categories of this paper are: eess
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The categories of this paper are: comp-gas
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The categories of this paper are: supr-con
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: bayes-an
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The categories of this paper are: cond-mat
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-ex