Packet-switched quantum networks require buffers that can delay qubit payloads while routing information is read out in real time. Previous approaches have not provided this functionality in a fully fibre-integrated architecture compatible with telecom infrastructure. Here we demonstrate an optical-fibre-integrated buffer, based on a recirculating loop and a fibre storage line, in which the storage time of a polarisation-encoded qubit payload is determined by readout of an attached packet header. The key component behind this achievement is an ultra-low-loss poled fibre phase modulator, which provides fast, polarisation-insensitive switching directly in fibre and allows header and payload to be processed within the buffer. We demonstrate storage and retrieval of polarisation-encoded qubit payloads for storage times up to 47 μs, with an average quantum bit error rate of 1.8

The paper describes the fabrication of two nanocomposite (NC) coated optical fibers, and their use to enhance the capabilities of distributed fiber sensing. The fibers are produced in a conventional optical fiber draw tower. NC coated fibers with reduced graphene oxide were shown to have enhanced mechanical durability at elevated temperatures and have a low humidity sensitivity compared to standard polyimide coated fibers. NC coated fibers with hydrogen-sensitive materials were shown to enable distributed hydrogen leak detection, in a configuration that is scalable to long lengths.

A new, modular approach to fibre-optic sensing is presented, where different types of optical fibres and other wires are combined to compact, hybrid cable assemblies, customized for each application. These fibre-optic assemblies can be embedded or integrated in various settings, enabling multi-parameter sensing and the measurement of new parameters. In this work, we describe the fabrication process of these miniature, multi-functional cables and how it can be directly used for sensing purposes in 3 end-user inspired applications.

Polymer coating layers are essential for the handling and proper function of optical fibers in their service environment. The analysis and monitoring of the elastic characteristics of coating layers are important for materials research and development, quality assurance, and maintenance. Most measurement protocols are destructive, require specialty samples, and may only be carried out offline. In this work, we monitor the velocities of dilatational acoustic waves in several coating layers of standard fibers, using forward Brillouin scattering processes. The measurements are non-destructive and performed over working fiber. Velocities are measured in three polyimide-based coating layers as functions of temperature up to 220 degrees C. Thermal changes in velocity are identified with 1% precision. The results suggest that the incorporation of nanoparticles within the polymer coating matrix improves its thermal stability.

Industry is transitioning from manually monitored components and processes to data-driven solutions. At the heart of this transformation is predictive maintenance, which relies on simultaneous, real-time monitoring of key operational parameters such as temperature and vibration to anticipate and prevent equipment failures. In this work, we present a modular approach to fibre-optic sensing, where different types of optical fibres and other wires are combined to compact, hybrid cable assemblies, customized for each application. These fibre-optic assemblies can be embedded or integrated in various settings, enabling multi-parameter sensing and the measurement of new parameters.

Dynamic storage of qubits is crucial for quantum communication networks. Here we present an adjustable buffer capable of storing photonic polarization quantum states in a fiber loop controllable by a poled fiber modulator.

Functional coatings on optical fibers enable selective detection of environmental and chemical parameters, but their use is typically limited to point or quasi-distributed sensing due to localized deposition techniques. In this work, we demonstrate a possible transition towards full-length functional coatings on optical fibers using a draw tower process, enabling their potential use in distributed sensor technology. An optical fiber with Pt:WO3 nanocomposite polymer functional coating is employed as a proof of concept. The results demonstrate the successful application of this functional coating along hundreds of meters of fibers using a draw tower. When integrated into a distributed sensing configuration, the Pt:WO3 fiber exhibited a clear change in response with varying hydrogen concentrations from 1% to 4% H2, with a temperature increase of 2.5 °C at 4 vol.% indicating a promising performance for distributed hydrogen leak detection. This approach opens new opportunities for applying other functional coatings over extended fiber lengths using draw towers, which could be exploited for novel distributed sensing applications.

The optical fibre coating is essential to ensure high performance and reliability of the optical fibre. Out of all polymer-coated fibres, polyimide coatings provide the highest temperature rating, typically rated for use in optical fibre sensing applications at 300˚C (in air), with short excursion to 350˚C. In this communication, we assess whether the inclusion of graphene-based nanoparticles, such as graphene and graphene oxide, in a polyimide coating can enhance the durability of optical fibres at high temperatures. Draw tower fabrication of optical fibres with nanocomposite polymer coating is described. Tensile strength tests, performed on aged nanocomposite-coated optical fibres, are used as an indication of their performance at harsh conditions. The results are validated and quantified by distributed temperature and humidity sensing tests performed using these fibres. The results show that this novel class of fibre is more robust to high-temperature ageing and moisture-induced strain than standard polyimide-coated fibres, when used for distributed sensing. The electrical conductivity of the nanocomposite coating is also used in a multi-sensing approach, together with distributed optical fibre sensing, to measure temperature in a reliable way using the same optical fibre.

A long length distributed hydrogen sensor was demonstrated for the first time, using a draw-tower fabricated optical fiber with a sensor coating that reacts exothermically in the presence of hydrogen in air.

An all-fiber setup to store and retrieve light pulses using electric control is presented. The experiment is based on a Sagnac interferometer with a phase modulator fabricated using a poled fiber with internal electrodes.

This paper presents a humidity-insensitive silicone coating compatible with draw tower production. It enables distributed humidity sensing since it can be used as reference fiber. Experimental findings demonstrate excellent humidity insensitivity (-20 to 45°C, 10-60%RH).

We present the design and fabrication of flexible, liquid-filled scintillating fibers for X-ray detection made from silica fibers and silica capillaries. The scintillating fibers were characterized using ultraviolet light exposure and we also performed an experiment demonstrating X-ray detection.

A fiber optic health-monitoring system for refractory lining in steel-making processes is presented. Its applicability as an early-warning system for lining damage is demonstrated by the results obtained in a field trial, in which 240 m of fiber was embedded in the lining of an electric arc furnace. The system is based on Raman distributed sensing and polyimide coated fibers in metal tube. The results presented from temperature cycling and calibration at temperatures up to 600 °C show that adequate accuracy and stability for the application can be attained.

fs-point-by-point through the coating written FBGs as a basis for novel sensor concepts using 25µm optical fiber. fs-point-by-point FBGs in novel single mode fiber with a cladding diameter of 25µm have been produced in fiber that is 5 times smaller than conventional telecommunication optical fiber. The development opens the path to new sensor types including miniature pressure sensors with a diameter of only 330µm (1Fr.)

Electrical corona discharge is employed in this work to deposit ions on the surface of an optical fiber, creating a strong electric field that is used for poling. Green laser light propagating in the core frees photocarriers that are displaced by the poling field. The technique presented can induce a higher optical nonlinearity than previously obtained in traditional optical poling with internal metal electrodes. To date, a maximum second order nonlinearity 0.13 pm/V has been achieved for a 15 kV corona discharge bias.

Ultrathin 25µm optical fibers with FBG sensors are manufactured and used as vibration sensors in glass-fiber reinforced composites. The use of ultrathin fibers is discussed, and their manufacture is described.

•The fiber Bragg gratings (FBG) were inscribed in single mode fibers with as-drawn 25 μm diameter cladding.•The sensing properties for temperature, strain, bending, and surrounding refractive index are studied experimentally.•The TFBGs show a relatively small number of narrow bandwidth (0.7 nm) cladding mode resonances.

Silicate optical fiber does not exhibit a linear electrooptic effect (Pockels’) because the material is symmetric. Poling can be used to induce the Pockels effect in pieces of fiber with electrodes by creating a permanent electric field by applying high voltage while the fiber is excited thermally [1] or optically [2] . The second-order nonlinear coefficient achieved reproducibly is χ (2) ≈ 0.1-0.3 pm/V. Optical poling uses short-wavelength light to excite the fiber core (e.g., from a UV lamp [3] ) as high voltage is applied to the internal fiber electrodes. Although the recorded field is limited by the voltage applied and silica’s dielectric breakdown strength, low loss devices can be fabricated. Here we describe the use of electrical corona discharge to pole fibers with high electric field across the fiber core. Charges deposited on the fiber surface (due to the electrical corona discharge) create the necessary poling field, as previously demonstrated in planar waveguides [4] .

PhotonicsViewsVolume 18, Issue 5 p. 1-1 EditorialFree Access Improve our visibiliy PhotonicSweden increases the awareness of the values created by photonics, and the importance of investing in the industry Åsa Claesson, Åsa Claesson Senior Scientist at RISE Research Institutes of Sweden Chair of the board of directors of PhotonicSwedenSearch for more papers by this author Åsa Claesson, Åsa Claesson Senior Scientist at RISE Research Institutes of Sweden Chair of the board of directors of PhotonicSwedenSearch for more papers by this author First published: 01 October 2021 https://doi.org/10.1002/phvs.202170501AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume18, Issue5October/November 2021Pages 1-1 RelatedInformation

This work combines fiber optic sensors with additive manufacturing to enable integration of temperature and strain sensors in metal components. In this paper, we present a fiber optic sensor network integrated in press hardening tools to monitor the contact between the tool and the metal sheet during forming operation. The tools are manufactured through metal powder bed fusion using laser melting processes (PBF-SLM), after which the tools are prepared for sensor integration. A demonstrator press hardening tool with integrated fiber optic sensors was heated using an electric heat foil and the sensor measurements was compared to a thermal simulation model. The sensor technology is based on Fiber Bragg Gratings (FBGs), integrated at several positions along the optical fiber. FBGs are in-fiber sensors that are multiplexed. lt is possible to place hundreds of FBG sensors along one single fiber, thus allowing for quasidistributed sensing of temperature or strain. The optical fiber itself can be less than 100 micrometer in diameter, allowing for sensing at several points in a minimally invasive way, when integrated in a tool or component.