Photonic contact thermometry using silicon ring resonators and tuneable laser-based spectroscopy

Photonic sensors offer the possibility of purely optical measurement in contact thermometry. In this work, silicon-based ring resonators were used for this purpose. These can be manufactured with a high degree of reproducibility and uniformity due to the established semiconductor manufacturing process. For the precise characterisation of these photonic sensors, a measurement setup was developed which allows laser-based spectroscopy around 1550 nm and stable temperature control from 5 °C to 95 °C. This was characterised in detail and the resulting uncertainty influences of both the measuring set-up and the data processing were quantified. The determined temperature stability at 20 °C is better than 0.51 mK for the typical acquisition time of 10 s for a 100 nm spectrum. For a measurement of >24 h at 30 °C a standard deviation of 2.6 mK could be achieved. A hydrogen cyanide reference gas cell was used for traceable in-situ correction of the wavelength. The determined correction function has a typical uncertainty of 0.6 pm. The resonance peaks of the ring resonators showed a high optical quality of 157 000 in the average with a filter depth of up to 20 dB in the wavelength range from 1525 nm to 1565 nm. When comparing different methods for the determination of the central wavelength of the resonance peaks, an uncertainty of 0.3 pm could be identified. A temperature-dependent shift of the resonance peaks of approx. 72 pm/K was determined. This temperature sensitivity leads together with the analysed uncertainty contributions to a repeatability of better than 10 mK in the analysed temperature range from 10 °C to 90 °C.Photonische Sensoren bieten die Möglichkeiten einer rein optischen Messung in der Berührungsthermometrie. In dieser Arbeit wurden hierfür siliziumbasierte Ringresonatoren verwendet. Diese lassen sich aufgrund der etablierten Halbleiterfertigung mit hoher Reproduzierbarkeit und Uniformität herstellen. Zur genauen Charakterisierung dieser photonischen Sensoren wurde ein Messplatz entwickelt, welcher eine laser-basierte Spektroskopie um 1550 nm und Thermostatisierung von 5 °C bis 95 °C ermöglicht. Dieser wurde ausführlich charakterisiert und resultierende Unsicherheitseinflüsse sowohl des Messplatzes als auch der Datenverarbeitung quantifiziert. Die ermittelte Temperatur-stabilitäten bei 20 °C ist besser als 0,51 mK für die typische Aufnahmezeit von 10 s eines 100 nm Spektrums. Für eine Messung von >24 h konnte bei 30 °C ein Standardabweichung von 2,6 mK erreicht werden. Eine Cyanwasserstoff-Referenzgaszelle diente zur rückführbaren in-situ Korrektur der Wellenlänge. Die ermittelte Korrekturfunktion hat hierbei typischerweise eine Unsicherheit von 0,6 pm. Die Resonanzpeaks der Ringresonatoren zeigten im Durschitt eine hohe optische Güte von 157 000 mit einer Filtertiefe von bis zu 20 dB im Wellenlängenbereich von 1525 nm bis 1565 nm. Beim Vergleich verschiedener Methoden zur Bestimmung der zentralen Wellenlänge der Resonanzpeaks konnte eine Unsicherheit von 0,3 pm ermittelt werden. Es wurde eine temperaturabhängige Verschiebung der Resonanzpeaks von ca. 72 pm/K bestimmt. Diese Temperatursensitivität führt mit den analysierten Unsicherheitsbeiträgen zu einer Wiederholbarkeit von besser als 10 mK im untersuchten Temperaturbereich von 10 °C bis 90 °C

Dimensioning of a multibeam coherent photonic beamformer fed by a phased array antenna.

The design and dimensioning of a photonic-aided payload for a multi-beam high-throughput communications satellite is a complex problem in which the antenna, RF and photonic subsystems must be considered as a whole for achieving best performance with lowest mass and power consumption. In this paper, we propose and dimension the receiving stage of a communications satellite comprising a phased array antenna (PAA) feeding a multibeam photonic beamforming system (PBS). The PBS uses a single wavelength and resorts to heterodyne detection such that the retrieved beams are frequency downconverted. End-to-end system modeling shows that the complexity of the PAA and PBS can be traded-off for signal-to-noise ratio (SNR) or power consumption without compromising the beam width. The dimensioning of a realistic scenario is presented, showing that an SNR and beam crosstalk on the order of 20 dB are achievable with a total power consumption below 1 kW for a typical number of 100 antenna elements (AEs)

Towards coherent O-band data center interconnects

Upcoming generations of coherent intra/inter data center interconnects currently lack a clear path toward a reduction of cost and power consumption, which are the driving factors for these data links. In this work, the tradeoffs associated with a transition from coherent C-band to O-band silicon photonics are addressed and evaluated. The discussion includes the fundamental components of coherent data links, namely the optical components, fiber link and transceivers. As a major component of these links, a monolithic silicon photonic BiCMOS O-band coherent receiver is evaluated for its potential performance and compared to an analogous C-band device.TU Berlin, Open-Access-Mittel - 2021BMBF, 13N14932, Verbundprojekt: Photonic Embedding of Active Region LASER Chips on Silicon (PEARLS) - Teilvorhaben: Entwurf und Charakterisierung von eingebetteten, horizontal-gekoppelten Laser-Strukturen auf SiliziumEC/H2020/822002/EU/Lasercom-on-chip for next generation, high-speed satellite constelation interconnectivity/ORIONA

Modular coherent photonic-aided payload receiver for communications satellites

Ubiquitous satellite communications are in a leading position for bridging the digital divide. Fulfilling such a mission will require satellite services on par with fibre services, both in bandwidth and cost. Achieving such a performance requires a new generation of communications payloads powered by large-scale processors, enabling a dynamic allocation of hundreds of beams with a total capacity beyond 1 Tbit s−1. The fact that the scale of the processor is proportional to the wavelength of its signals has made photonics a key technology for its implementation. However, one last challenge hinders the introduction of photonics: while large-scale processors demand a modular implementation, coherency among signals must be preserved using simple methods. Here, we demonstrate a coherent photonic-aided receiver meeting such demands. This work shows that a modular and coherent photonic-aided payload is feasible, making way to an extensive introduction of photonics in next generation communications satellites

Photonic and Optomechanical Thermometry

Temperature is one of the most relevant physical quantities that affects almost all processes in nature. However, the realization of accurate temperature standards using current temperature references, like the triple point of water, is difficult due to the requirements on material purity and stability of the environment. In addition, in harsh environments, current temperature sensors with electrical readout, like platinum resistors, are difficult to implement, urging the development of optical temperature sensors. In 2018, the European consortium Photoquant, consisting of metrological institutes and academic partners, started investigating new temperature standards for self-calibrated, embedded optomechanical sensor applications, as well as optimised high resolution and high re- liability photonic sensors, to measure temperature at the nano and meso-scales and as a possible replacement for the standard platinum resistant thermometers. This article presents an overview of the results obtained with sensor prototypes that exploit photonic and optomechanical techniques for sensing temperatures over a large temperature range (5 K to 300 K). Different concepts are demon- strated, including ring resonators, ladder-like resonators and suspended membrane optomechanical thermometers, highlighting initial performance and challenges, like self-heating that need to be overcome to realize photonic and optomechanical thermometry applications.This work was carried out under the 17FUN05 PhotOQuanT project, which has received funding from the EMPIR program, co-financed by the Participating States and the European Union’s Horizon 2020 research and innovation progra

Overcoming degradation in spatial multiplexing systems with stochastic nonlinear impairments

Single-mode optical fibres now underpin telecommunication systems and have allowed continuous increases in traffic volume and bandwidth demand whilst simultaneously reducing cost- and energy-per-bit over the last 40 years. However, it is now recognised that such systems are rapidly approaching the limits imposed by the nonlinear Kerr effect. To address this, recent research has been carried out into mitigating Kerr nonlinearities to increase the nonlinear threshold and into spatial multiplexing to offer additional spatial pathways. However, given the complexity associated with nonlinear transmission in spatial multiplexed systems subject to random inter-spatial-path nonlinearities it is widely believed that these technologies are mutually exclusive. By investigating the linear and nonlinear crosstalk in few-mode fibres based optical communications, we numerically demonstrate, for the first time, that even in the presence of significant random mixing of signals, substantial performance benefits are possible. To achieve this, the impact of linear mixing on the Kerr nonlinearities should be taken into account using different compensation strategies for different linear mixing regimes. For the optical communication systems studied, we demonstrate that the performance may be more than doubled with the appropriate selection of compensation method for fibre characteristics which match those presented in the literature

Entwicklung einer anforderungsgerechten Mobilitätsassistenz für in ihrer Mobilität eingeschränkte Reisende

Der öffentliche Personennahverkehr (ÖPNV) ist einer der wichtigsten Grundpfeiler einer nachhaltigen Mobilität in Ballungsräumen. Er sichert neben der gleichberechtigten Teilhabe aller Bürgerinnen und Bürger am gesellschaftlichen Leben auch die wirtschaftliche Leistungsfähigkeit des Industriestandortes Deutschland. Alle Nutzergruppen und deren spezifische Anforderungsprofile müssen in der Planung und betrieblichen Abwicklung des öffentlichen Verkehrs Berücksichtigung finden. Insbesondere die Entwicklung neuartiger Konzepte für in ihrer Mobilität eingeschränkte Reisende erfordert eine umfassende Betrachtung ihrer spezifischen Nutzerbedürfnisse. Ausgangspunkt der Entwicklung eines solchen Reiseassistenzkonzepts für den ÖPNV, ist eine grundlegende Betrachtung der Leistungserbringung im ÖPNV. Diese Kernprozesse der Verkehrsunternehmen im ÖPNV müssen abgebildet werden um sie anschließend mit den Kundenprozessen und den aus diesen resultierenden Anforderungen zu verbinden. Dieser Artikel legt dar, wie ein solches, neu zu entwickelndes barrierefreies Mobilitätskonzept systematisch und kundenorientiert erarbeitet werden kann. Hierbei wird auf Ansätze für die Schaffung eines Abbildes des Leistungserbringungsprozesses im ÖPNV, einem Anforderungsmanagement für ÖPNV Netzwerke wie auch der Implementierung von kontinuierlichen Kundenzufriedenheitsmessungen zur Messung der Anforderungserfüllung für den ÖPNV eingegangen. Neben der Erarbeitung der neuen Methodik soll ein umfassendes, leicht übertragbares Mobilitätskonzept geschaffen werden, um bestehende Nutzungsbarrieren des ÖPNV in urbanen Räumen für alle Beteiligten nachhaltig abzubauen

Accessible and inclusive mobility for all with individual travel assistance - aim4it

Public transportation is a main factor for a reliable mobility in urban and rural areas. Every user group and their specific requirements have to be considered during planning and realization of public transportation services. Hence public transport operators have to ensure a barrier-free public transportation service. Certainly this barrier-freeness still is not realized for every user group, due to the high complexity of public transportation systems. Therefore this paper focuses on a comprehensive Systems Engineering based approach to handle complexity for development of a new individual travel assistance and its integration into existing background systems of public transport operators. This approach is based on several use-cases. One use-case will be focused on for an exemplary system introduction

Barrierfree Mobility for All by a Smart and Individual Travel Assistance

Public transport operators focus on a public transport system which is inclusive and fair to all groups of society. This requires a holistic approach, which considers the user and the service provider perspective. From the passengers’ view, it becomes obvious that not only the accessibility of a single transportation system is relevant. The interchanges within the system as well as the change-over to other systems must be improved regarding the special requirements of people with reduced mobility and/or sensory restrictions. This article describes how this objective can be achieved in the project aim4it by an individual and smart solution, which is available and useable for every passenger-group. System components are presented and first results are pointed out