Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Understanding photoluminescence in semiconductor Bragg-reflection
  waveguides: Towards an integrated, GHz-rate telecom photon pair source   Compared to traditional nonlinear optical crystals, like BaB$_2$O$_4$,
KTiOPO$_4$ or LiNbO$_3$, semiconductor integrated sources of photon pairs may
operate at pump wavelengths much closer to the bandgap of the materials. This
is also the case for Bragg-reflection waveguides (BRW) targeting parametric
down-conversion (PDC) to the telecom C-band. The large nonlinear coefficient of
the AlGaAs alloy and the strong confinement of the light enable extremely
bright integrated photon pair sources. However, under certain circumstances, a
significant amount of detrimental broadband photoluminescence has been observed
in BRWs. We show that this is mainly a result of linear absorption near the
core and subsequent radiative recombination of electron-hole pairs at deep
impurity levels in the semiconductor. For PDC with BRWs, we conclude that
devices operating near the long wavelength end of the S-band or the short
C-band require temporal filtering shorter than 1 ns. We predict that shifting
the operating wavelengths to the L-band and making small adjustments in the
material composition will reduce the amount of photoluminescence to negligible
values. Such measures enable us to increase the average pump power and/or the
repetition rate, which makes integrated photon pair sources with on-chip
multi-gigahertz pair rates feasible.

1
The categories of this paper are: cs
16
The categories of this paper are: stat
26
The categories of this paper are: bayes-an
24
The categories of this paper are: dg-ga
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
6
The categories of this paper are: astro-ph
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
31
The categories of this paper are: ao-sci
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg