[show abstract][hide abstract] ABSTRACT: Quantum photonic integration circuits are a promising approach to scalable
quantum processing with photons. Waveguide single-photon-detectors (WSPDs)
based on superconducting nanowires have been recently shown to be compatible
with single-photon sources for a monolithic integration. While standard WSPDs
offer single-photon sensitivity, more complex superconducting nanowire
structures can be configured to have photon-number-resolving capability. In
this work, we present waveguide photon-number-resolving detectors (WPNRDs) on
GaAs/Al0.75Ga0.25As ridge waveguides based on a series connection of nanowires.
The detection of 0-4 photons has been demonstrated with a four-wire WPNRD,
having a single electrical read-out. A device quantum efficiency ~24 % is
reported at 1310 nm for the TE polarization.
[show abstract][hide abstract] ABSTRACT: We demonstrate an integrated autocorrelator based on two superconducting single-photon detectors patterned on top of a GaAs ridge waveguide. This device enables the on-chip measurement of the second-order intensity correlation function g<sup>(2)</sup>(τ). A polarization-independent device quantum efficiency in the 1% range is reported, with a timing jitter of 88 ps at 1300 nm. g<sup>(2)</sup>(τ) measurements of continuous-wave and pulsed laser excitations are demonstrated with no measurable crosstalk within our measurement accuracy.
[show abstract][hide abstract] ABSTRACT: A new step toward full on-chip integration of active elements (singlephoton detectors) and passive elements (quantum photonic circuits) enables important functionalities in quantum information processing
[show abstract][hide abstract] ABSTRACT: We demonstrate tunable on-chip single photon sources using the Stark tuning of single quantum dot (QD) excitonic transitions in short photonic crystal waveguides (PhC WGs). The emission of single QDs can be tuned in real-time by 9 nm with an applied bias voltage less than 2V. Due to a reshaped density of optical modes in the PhC WG, a large coupling efficiencyβ≥65%to the waveguide mode is maintained across a wavelength range of 5 nm. When the QD is resonant with the Fabry-Perot mode of the PhC WG, a strong enhancement of spontaneous emission is observed leading to a maximum coupling efficiencyβ=88%. These results represent an important step towards the scalable integration of single photon sources in quantum photonic integrated circuits.
[show abstract][hide abstract] ABSTRACT: Efficient sources of indistinguishable single photons are a key resource
for various applications in fields like quantum sensing, quantum
metrology and quantum information processing. In this contribution we
report on single photon generation based on III-V semiconductor quantum
dots (QDs). To increase the emission efficiency of single photons, it is
essential to tailor the radiative properties of the quantum dot emitters
by engineering their photonic environment. We present optimized single
photon emitters being based on both micropillar and photonics crystal
cavities, for applications in a vertical platform and on-chip in-plane
platform, respectively. Electrically driven single photon sources with
self assembled semiconductor QDs embedded into GaAs/AlAs micropillar
cavities emit on demand net rates of ~35 MHz single photons, thus being
well exploitable in quantum key distribution systems. In order to
establish also a spatially deterministic fabrication platform, position
controlled quantum dots are integrated into p-i-n micropillar cavities
and single photon emission of a coupled QD-micropillar diode system is
observed. Efficient broadband coupling of single photons into photonic
crystal waveguides provides the basis for all on-chip quantum
information processing, and an according approach is reported.
[show abstract][hide abstract] ABSTRACT: We report a study of the quantum dot emission in short photonic crystal
waveguides. We observe that the quantum dot photoluminescence intensity and
decay rate are strongly enhanced when the emission energy is in resonance with
Fabry-Perot cavity modes in the slow-light regime of the dispersion curve. The
experimental results are in agreement with previous theoretical predictions and
further supported by three-dimensional finite element simulation. Our results
show that the combination of slow group velocity and Fabry-Perot cavity
resonance provides an avenue to efficiently channel photons from quantum dots
into waveguides for integrated quantum photonic applications.
[show abstract][hide abstract] ABSTRACT: We demonstrate waveguide single-photon detectors based on NbN nanowires on top of GaAs/AlGaAs ridge waveguides. High quantum efficiencies of ~20% at 1300 nm with a response time of 3.6ns and timing jitter of ~60ps are reported.
[show abstract][hide abstract] ABSTRACT: Superconducting nanowires can be used to detect single photons with very high sensitivity
and speed in the near-infrared. We present recent results on single-photon detectors integrated with
microcavities and waveguides for increased efficiency, and photon-number-resolving detectors based
on arrays of nanowires.
[show abstract][hide abstract] ABSTRACT: Progress towards the development of a quantum integrated photonics platform on GaAs will be reported, including on-chip single photon sources, detectors, splitters, couplers and modulators.
Optoelectronic and Microelectronic Materials & Devices (COMMAD), 2012 Conference on. 01/2012;
[show abstract][hide abstract] ABSTRACT: The implementation of single-photon detectors in waveguide photonic circuits will open the possibility of experiments in quantum regime that would otherwise be impossible to be implemented using bulk optics. Nanowire superconducting single-photon detectors (SSPDs) are good candidates for integration due to their relative ease of fabrication on top of GaAs heterostructures. In this paper we show the experimental demonstration of single-photon detectors, based on superconducting nanowires, fully integrated with GaAs/AlGaAs ridge waveguides. We will discuss all the major challenges surmounted and all the steps necessary to achieve these results.
[show abstract][hide abstract] ABSTRACT: The generation, manipulation and detection of quantum bits (qubits) encoded
on single photons is at the heart of quantum communication and optical quantum
information processing. The combination of single-photon sources, passive
optical circuits and single-photon detectors enables quantum repeaters and
qubit amplifiers, and also forms the basis of all-optical quantum gates and of
linear-optics quantum computing. However, the monolithic integration of
sources, waveguides and detectors on the same chip, as needed for scaling to
meaningful number of qubits, is very challenging, and previous work on quantum
photonic circuits has used external sources and detectors. Here we propose an
approach to a fully-integrated quantum photonic circuit on a semiconductor
chip, and demonstrate a key component of such circuit, a waveguide
single-photon detector. Our detectors, based on superconducting nanowires on
GaAs ridge waveguides, provide high efficiency (20%) at telecom wavelengths,
high timing accuracy (60 ps), response time in the ns range, and are fully
compatible with the integration of single-photon sources, passive networks and
[show abstract][hide abstract] ABSTRACT: We report the first waveguide single-photon detectors. They are based on superconducting nanowires patterned on top of GaAs/AlGaAs waveguides and are suitable for monolithic integration with single-photon sources and passive quantum optical networks. The combination of single-photon sources, passive optical circuits and single-photon detectors enables important functionalities in quantum communications, such as quantum repeaters (1) and qubit amplifiers (2), and also forms the basis of all-optical quantum gates (3) and of linear-optics quantum computing (4). However, present implementations are limited to few qubits, due to the large number of optical components required and the corresponding complexity and cost of experimental set-ups. The monolithic integration of quantum photonic components and circuits on a chip is absolutely required to scale implementations of optical quantum information processing to meaningful numbers of qubits. The integration of passive circuits has been demonstrated in the silica- on-silicon platform (5), but an approach to the simultaneous integration of sources, detectors and passive circuitry is still missing. The integration of detectors is particularly challenging, as the complex device structures associated to avalanche photodiodes are not easily compatible with the integration with low-loss waveguides and even less with sources. Here we report a simple approach to the realization of single-photon detectors on optical waveguides in the GaAs/AlGaAs material system. It enables the first demonstration of waveguide single-photon detectors and is fully compatible with the monolithic integration of detectors with single-photon sources (based on InAs quantum dots) and passive optical circuits on a single chip. Our waveguide single-photon detectors (WSPDs) are based on the principle of photon-induced hot-spot creation in ultranarrow superconducting NbN wires, which is at the basis of nanowire single-photon detectors (SSPDs) (6) and can provide ultrahigh sensitivity at telecommunication wavelengths, high counting rates, broad spectral response and high temporal resolution due to low jitter values. For WSPDs, the wires are deposited and patterned on top of a GaAs/AlGaAs ridge waveguide, in order to sense the evanescent field on the surface (Fig. 1). The calculated modal absorption coefficient for the fundamental transverse-electric mode of a 1.85 μm-wide waveguide, in the presence of four 4 nm-thick and 100 nm-wide NbN wires is as high as 450 cm
[show abstract][hide abstract] ABSTRACT: We report a study on single photons emitted by single quantum dots into ridge and photonic crystal waveguides using an extended micro-photoluminescence setup. Our results show promise for future applications in quantum photonic integrated circuits.