@article{60136,
abstract = {{Modulation conditioned on measurements on entangled photonic quantum states is a cornerstone technology of optical quantum information processing. Performing this task with low latency requires combining single-photon-level detectors with both electronic logic processing and optical modulation in close proximity. Here, we demonstrate low-latency feedforward using a quasi-photon-number-resolved measurement on a quantum light source. Specifically, we use a multipixel superconducting nanowire single-photon detector, amplifier, logic, and an integrated electro-optic modulator in situ below 4 K. We modulate the signal mode of a spontaneous parametric down-conversion source, conditional on a photon-number measurement of the idler mode, with a total latency of (23±3)ns. Furthermore, we investigate the resulting change in the photon statistics. This represents an important benchmark for the fastest quantum photonic feedforward experiments comprising measurement, amplification, logic, and modulation. This has direct applications in quantum computing, communication, and simulation protocols.}},
author = {{Thiele, Frederik and Lamberty, Niklas and Hummel, Thomas and Lange, Nina Amelie and Procopio Peña, Lorenzo Manuel and Barua, Aishi and Lengeling, Sebastian and Quiring, Viktor and Eigner, Christof and Silberhorn, Christine and Bartley, Tim}},
issn = {{2334-2536}},
journal = {{Optica}},
number = {{5}},
publisher = {{Optica Publishing Group}},
title = {{{Cryogenic feedforward of a photonic quantum state}}},
doi = {{10.1364/optica.551287}},
volume = {{12}},
year = {{2025}},
}
@article{55553,
abstract = {{Cryogenic opto-electronic interconnects are gaining increasing interest as a means to control and readout cryogenic electronic components. The challenge is to achieve sufficient signal integrity with low heat load processing. In this context, we demonstrate the opto-electronic bias and readout of a commercial four-pixel superconducting nanowire single-photon detector array using a cryogenic photodiode and laser. We show that this approach has a similar system detection efficiency to a conventional bias. Furthermore, multi-pixel detection events are faithfully converted between the optical and electrical domains, which allows reliable extraction of amplitude multiplexed photon statistics. Our device has a latent heat load of 2.6 mW, maintains a signal rise time of 3 ns, and operates in free-running (self-resetting) mode at a repetition rate of 600 kHz. This demonstrates the potential of high-bandwidth, low noise, and low heat load opto-electronic interconnects for scalable cryogenic signal processing and transmission.}},
author = {{Thiele, Frederik and Lamberty, Niklas and Hummel, Thomas and Bartley, Tim}},
issn = {{2378-0967}},
journal = {{APL Photonics}},
number = {{7}},
publisher = {{AIP Publishing}},
title = {{{Optical bias and cryogenic laser readout of a multipixel superconducting nanowire single photon detector}}},
doi = {{10.1063/5.0209458}},
volume = {{9}},
year = {{2024}},
}
@article{51356,
abstract = {{Abstract
Lithium niobate has emerged as a promising platform for integrated quantum optics, enabling efficient generation, manipulation, and detection of quantum states of light. However, integrating single-photon detectors requires cryogenic operating temperatures, since the best performing detectors are based on narrow superconducting wires. While previous studies have demonstrated the operation of quantum light sources and electro-optic modulators in LiNbO3 at cryogenic temperatures, the thermal transition between room temperature and cryogenic conditions introduces additional effects that can significantly influence device performance. In this paper, we investigate the generation of pyroelectric charges and their impact on the optical properties of lithium niobate waveguides when changing from room temperature to 25 K, and vice versa. We measure the generated pyroelectric charge flow and correlate this with fast changes in the birefringence acquired through the Sénarmont-method. Both electrical and optical influence of the pyroelectric effect occur predominantly at temperatures above 100 K.}},
author = {{Thiele, Frederik and Hummel, Thomas and Lange, Nina Amelie and Dreher, Felix and Protte, Maximilian and Bruch, Felix vom and Lengeling, Sebastian and Herrmann, Harald and Eigner, Christof and Silberhorn, Christine and Bartley, Tim}},
issn = {{2633-4356}},
journal = {{Materials for Quantum Technology}},
keywords = {{General Earth and Planetary Sciences, General Environmental Science}},
number = {{1}},
publisher = {{IOP Publishing}},
title = {{{Pyroelectric influence on lithium niobate during the thermal transition for cryogenic integrated photonics}}},
doi = {{10.1088/2633-4356/ad207d}},
volume = {{4}},
year = {{2024}},
}
@article{48399,
abstract = {{Quantum photonic processing via electro-optic components typically requires electronic links across different operation environments, especially when interfacing cryogenic components such as superconducting single photon detectors with room-temperature control and readout electronics. However, readout and driving electronics can introduce detrimental parasitic effects. Here we show an all-optical control and readout of a superconducting nanowire single photon detector (SNSPD), completely electrically decoupled from room temperature electronics. We provide the operation power for the superconducting detector via a cryogenic photodiode, and readout single photon detection signals via a cryogenic electro-optic modulator in the same cryostat. This method opens the possibility for control and readout of superconducting circuits, and feedforward for photonic quantum computing.}},
author = {{Thiele, Frederik and Hummel, Thomas and McCaughan, Adam N. and Brockmeier, Julian and Protte, Maximilian and Quiring, Victor and Lengeling, Sebastian and Eigner, Christof and Silberhorn, Christine and Bartley, Tim}},
issn = {{1094-4087}},
journal = {{Optics Express}},
keywords = {{Atomic and Molecular Physics, and Optics}},
number = {{20}},
publisher = {{Optica Publishing Group}},
title = {{{All optical operation of a superconducting photonic interface}}},
doi = {{10.1364/oe.492035}},
volume = {{31}},
year = {{2023}},
}
@article{33672,
abstract = {{Abstract
Lithium niobate is a promising platform for integrated quantum optics. In this platform, we aim to efficiently manipulate and detect quantum states by combining superconducting single photon detectors and modulators. The cryogenic operation of a superconducting single photon detector dictates the optimisation of the electro-optic modulators under the same operating conditions. To that end, we characterise a phase modulator, directional coupler, and polarisation converter at both ambient and cryogenic temperatures. The operation voltage
V
π
/
2
of these modulators increases, due to the decrease in the electro-optic effect, by 74% for the phase modulator, 84% for the directional coupler and 35% for the polarisation converter below 8.5
K
. The phase modulator preserves its broadband nature and modulates light in the characterised wavelength range. The unbiased bar state of the directional coupler changed by a wavelength shift of 85
n
m
while cooling the device down to 5
K
. The polarisation converter uses periodic poling to phasematch the two orthogonal polarisations. The phasematched wavelength of the utilised poling changes by 112
n
m
when cooling to 5
K
.}},
author = {{Thiele, Frederik and vom Bruch, Felix and Brockmeier, Julian and Protte, Maximilian and Hummel, Thomas and Ricken, Raimund and Quiring, Viktor and Lengeling, Sebastian and Herrmann, Harald and Eigner, Christof and Silberhorn, Christine and Bartley, Tim}},
issn = {{2515-7647}},
journal = {{Journal of Physics: Photonics}},
keywords = {{Electrical and Electronic Engineering, Atomic and Molecular Physics, and Optics, Electronic, Optical and Magnetic Materials}},
number = {{3}},
publisher = {{IOP Publishing}},
title = {{{Cryogenic electro-optic modulation in titanium in-diffused lithium niobate waveguides}}},
doi = {{10.1088/2515-7647/ac6c63}},
volume = {{4}},
year = {{2022}},
}
@article{33673,
abstract = {{ Superconducting Nanowire Single Photon Detectors (SNSPDs) have become an integral part of quantum optics in recent years because of their high performance in single photon detection. We present a method to replace the electrical input by supplying the required bias current via the photocurrent of a photodiode situated on the cold stage of the cryostat. Light is guided to the bias photodiode through an optical fiber, which enables a lower thermal conduction and galvanic isolation between room temperature and the cold stage. We show that an off-the-shelf InGaAs–InP photodiode exhibits a responsivity of at least 0.55 A/W at 0.8 K. Using this device to bias an SNSPD, we characterize the count rate dependent on the optical power incident on the photodiode. This configuration of the SNSPD and photodiode shows an expected plateau in the single photon count rate with an optical bias power on the photodiode above 6.8 µW. Furthermore, we compare the same detector under both optical and electrical bias, and show there is no significant changes in performance. This has the advantage of avoiding an electrical input cable, which reduces the latent heat load by a factor of 100 and, in principle, allows for low loss RF current supply at the cold stage. }},
author = {{Thiele, Frederik and Hummel, Thomas and Protte, Maximilian and Bartley, Tim}},
issn = {{2378-0967}},
journal = {{APL Photonics}},
keywords = {{Computer Networks and Communications, Atomic and Molecular Physics, and Optics}},
number = {{8}},
publisher = {{AIP Publishing}},
title = {{{Opto-electronic bias of a superconducting nanowire single photon detector using a cryogenic photodiode}}},
doi = {{10.1063/5.0097506}},
volume = {{7}},
year = {{2022}},
}
@article{26221,
author = {{Bartnick, Moritz and Santandrea, Matteo and Höpker, Jan Philipp and Thiele, Frederik and Ricken, Raimund and Quiring, Viktor and Eigner, Christof and Herrmann, Harald and Silberhorn, Christine and Bartley, Tim}},
issn = {{2331-7019}},
journal = {{Physical Review Applied}},
title = {{{Cryogenic Second-Harmonic Generation in Periodically Poled Lithium Niobate Waveguides}}},
doi = {{10.1103/physrevapplied.15.024028}},
year = {{2021}},
}
@article{20157,
author = {{Thiele, Frederik and vom Bruch, Felix and Quiring, Victor and Ricken, Raimund and Herrmann, Harald and Eigner, Christof and Silberhorn, Christine and Bartley, Tim}},
issn = {{1094-4087}},
journal = {{Optics Express}},
title = {{{Cryogenic electro-optic polarisation conversion in titanium in-diffused lithium niobate waveguides}}},
doi = {{10.1364/oe.399818}},
year = {{2020}},
}