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We present a scalable and novel modular optical metro core node architecture employing photonic WDM integrated switches. Multi-degree switching ROADM nodes are used at the metro-core level, while access network is constituted by low-cost ROADM nodes. Photonic integrated switches have been designed as the building blocks to realize this modular metro node architectures, namely photonic WDM space switches with express and add/drop ports, photonic integrated WSS aggregation/disaggregation functions for merging/dropping the network traffic, and photonic integrated multi-cast switch (MCS), to achieve, together with bandwidth variable transceivers aggregators, multi-Terabits/second operation per link. In particular, photonic WDM space switches and photonic integrated WSS are designed as building blocks to realize this novel modular metro node architectures. Moreover, dynamic re-configurable metro-access nodes based on low-cost photonic integrated mini-ROADMs will be presented. The lossless photonic WDM switches are based on InP technology and employ semiconductor optical amplifiers as on-chip gain element and for fast switching. The photonic WDM circuits allow to switch multiple format data signals in wavelength, space and time for full flexibility, scalability of the interconnected network elements, as well as capacity. Applications will be discussed and experimental results will be reported. Finally advances in compact photonic integrated InP switch design using the InP generic technology will be discussed.

We present a scalable and novel modular optical metro core node architecture and low cost metro access node architectures with edge computing functionalities employing photonic WDM integrated switches. Photonic integrated switches has been designed as the building blocks to realize the modular metro node architectures, namely photonic WDM switches with express and add/drop ports, photonic integrated WSS aggregation/disaggregation functions for merging/dropping the network traffic, and photonic integrated multi-cast switch (MCS), as well as bandwidth variable transceivers aggregators to achieve multi-Terabits/second operation. Moreover, a dynamic re-configurable metro-access nodes based on low-cost 2-degree photonic integrated mini-ROADMs will be discussed. The lossless photonic WDM switches are based on InP technology and employ semiconductor optical amplifiers as on-chip gain element and fastswitch. The photonic WDM circuits allows to switch multiple format data signals in wavelength, space, and time for full flexibility, scalability of the interconnected network elements as well as capacity. Applications to data center interconnects and 5G will be discussed and experimental results reported.

We successfully demonstrate classification of three classes of Iris flowers by implementing a trained neural network on an SOA-based InP cross-connect chip. Classification accuracy of 91.6% is achieved after a fine optimization procedure.

Hydrogenated amorphous silicon (a-Si:H) is known to exhibit light-induced metastable properties that are reversible upon annealing. Although these metastable properties suggest the existence of reversible optical properties of a-Si:H as well, very little is known about this effect. If indeed properly identified and characterized, such reversible optical properties may find application in the reversible programmable photonic integrated circuits (PICs) that can enable multiple functionalities on the same chip, similar to field-programmable gate arrays (FPGAs). However, the required reversible effective refractive index change due to light soaking and annealing has not been reported yet nor has it been thoroughly investigated. Therefore, the effects of prolonged high intensity light soaking and annealing on a-Si:H on the near infrared (NIR) optical properties are studied in this work. A thin-film interferometric technique was developed to detect minute changes probed using a NIR laser source (1465-1575 nm). Using this approach, an increase in refractive index resulted in a red shift of the sharp reflection minimum and a blue shift for the decrease in refractive index. To detect the changes in optical properties more precisely, double-layered thin films were used: a-Si:H was deposited by inductively coupled plasma-enhanced chemical vapour deposition (ICP-PECVD) on SiO2, which was in turn deposited by PECVD on a crystalline silicon substrate. The a-Si:H deposition temperature was set to 80 °C and 300 °C, such that significantly different structural properties, e.g. hydrogen content and density, could be achieved. An irreversible blue shift was observed during the first cycle of annealing and light soaking after the deposition. However, from the second cycle onwards, a red shift of the spectrum due to light soaking, i.e. reversal of the annealed state was observed. It appeared that the initial irreversible changes are inevitable and only after these changes reversibility is observable. The reversibility was sustained after further cycles of annealing and light soaking. The reversibility appears for both a-Si:H deposited at 80 °C and 300 °C. However, the magnitude of the reversibility for a-Si:H deposited at 80 °C is significantly larger when compared to a-Si:H deposited at 300 °C. This suggests a correlation of the metastable properties of a-Si:H on the hydrogen content and density of the material, i.e. porous films (deposited at 80 °C) are more susceptible to light-induced change than dense films (deposited at 300 °C). The magnitude of the reversibility in refractive index for a-Si:H deposited at 80 °C is estimated to be around 0.03%. Although small, this metastable change should be sufficient for an application in reversible programmable optical switch. These results therefore indicate that a-Si:H has potential in enabling reversible programmable PICs and work to implement this material in a photonic device is currently ongoing.

This article explores the background of anatomical educational research. It draws together research and our own personal experiences to propose a best practice piece for novice researchers in anatomical education. The article explores the domains of both qualitative, and quantitative methods as applied to anatomy pedagogy. It takes into consideration validity and what might be undertaken to increase validity and reliability. The article explores how both qualitative and quantitative data can be analysed and recommends top tips including: Identify your research questions and theoretical framework. Map out how you are going to answer your research questions. Consider collaborating with like-minded researchers in other countries:\ud multi-centre studies have a better chance of getting published and carefully consider your target\ud journal and suggestions for peer review, taking into consideration individuals expertise and\ud potential conflicts of interests. This article is designed to be a guide to anyone starting\ud anatomical research or experienced researchers looking for new methods and ideas.

A voltage driven InP/InGaAsP 1x2 optical switch based on multimode interference (MMI) and with potential for polarization insensitive routing is proposed and numerically studied. Continuous in plane beam steering across the output cross section of a 20 μm wide waveguide enables optical switching between two symmetric 8 μm wide output waveguides. Two twin electrodes on top of the 20 μm wide waveguide are tuned with reverse bias voltage to switch output port by reconfiguration of the refractive index profile. The numerical prediction of the device performance is provided by combining a calibrated model of the voltage perturbed refractive index and absorption with electrical and optical solvers. Simulation results show that an extinction ratio of 29 dB can be achieved at an optical wavelength of 1550 nm and with a switching voltage of -12 V.

The vast majority of Staebler-Wronski Effect(SWE) studies have been focused on understanding the nature of metastable defects in hydrogenated amorphous silicon(a-Si:H), i.e. the optoelectrical properties for photon energies below the bandgap. However, the effects of prolonged light exposure and annealing on the optoelectrical properties above the bandgap have not been thoroughly investigated. For photonic integrated circuits even refractive index changes as little as 1%, may have a significant impact. Therefore, this work aims to study possible changes in the absorption properties above the bandgap as enabled by high intensity visible light soaking and annealing. The parameter used in this work to study such changes in absorption is the imaginary part of the pseudo dielectric function derived by spectroscopic ellipsometric (SE) measurements. A set of a-Si:H films was deposited near the amorphous/nanocrystalline phase transition at different substrate temperatures having different microstructures by inductively coupled plasma enhanced chemical vapour deposition(ICP-PECVD). For an a-Si:H film the value exhibits considerable change over time, as the top surface undergoes oxidation during prolonged air exposure. Therefore, the light-induced and annealing effects on these samples are investigated with respect to the corresponding twin samples that are stored at room temperature in air to serve as a reference. The measured values around the electronic polarization resonance clearly decrease after light soaking and can be completely reversed after annealing (nearly 4%; see attached figures), indicating familiar metastable nature of defects in hydrogenated amorphous silicon. Since no loss of bonded hydrogen is detected after repeated light soaking and annealing cycles and considering the reversibility of the change, it is believed that a change in the bulk optical properties is the main contributor to the observed metastable effect suggesting reversible refractive index change. Optical simulations which take the sample surface oxidation into account suggest that the effect may be explained through metastable volumetric expansion.

A lateral beam steering device based on electro-optic effects in an InP/InGaAsP expanded mode waveguide has been designed, simulated and tested. Experimental results confirm that submicron precision beam movement is achieved at the output facet of the device. A total tuning range of 0.8 µm has been measured.

We present InP as the incumbent technology for data center transceiver and switching optics. We review the most popular InP monolithic integration approaches in light of photonic integration being recognized as an increasingly important technology for data center optics. We present Multi-Guide Vertical Integration by OneChip Photonics as an example of a low-cost InP integration platform, showcased for 100GE transceiver optics, and we also review optical switching technology and present highly integrated InP optical switches developed at the COBRA Research Institute. We compare InP to the competing Si photonics technology, where we argue that Si photonics is a cost-competitive technology, but only for very large volumes, which are not yet representative of the data center market of today and in the near future. We conclude by pinpointing the future trends for the optics in data centers, including the increased level of optics/electronics integration, the increased use of spin-coated polymer devices, and novel heterogeneous integration by flip-chip bonding of separately fabricated InP and Si chips, as an alternative to the more challenging, full monolithic InP integration.