Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Fully tunable and switchable coupler for photonic routing in quantum
  detection and modulation   Photonic routing is a key building block of many optical applications
challenging its development. We report a 2$\times$2 photonic coupler with
splitting ratio switchable by a low-voltage electronic signal with 10~GHz
bandwidth and tens of nanoseconds latency. The coupler can operate at any
splitting ratio ranging from 0:100 to 100:0 with the extinction ratio of 26 dB
in optical bandwidth of 1.3 THz. We show sub-nanosecond switching between
arbitrary coupling regimes including balanced 50:50 beam splitter, 0:100
switch, and a photonic tap. The core of the device is based on Mach-Zehnder
interferometer in a dual-wavelength configuration allowing real-time phase lock
with long-term sub-degree stability at single-photon level. Using the reported
coupler, we demonstrate for the first time the perfectly balanced
time-multiplexed device for photon-number-resolving detectors and also the
active preparation of a photonic temporal qudit state up to four time bins.
Verified long-term stable operation of the coupler at the single photon level
makes it suitable for wide application range in quantum information processing
and quantum optics in general.

34
The categories of this paper are: chem-ph
7
The categories of this paper are: hep-th
31
The categories of this paper are: ao-sci
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
8
The categories of this paper are: hep-ex
14
The categories of this paper are: math-ph
17
The categories of this paper are: q-fin
16
The categories of this paper are: stat