Information and Communication Technology (ICT) is increasingly important in our daily life, but it is also a major consumer of energy. Thus, the main ICT societal challenges are to become faster and more energy-efficient. To meet both demands, photonics technology allows replacing electronic by optical transmission, while data processing affords higher bandwidths at reduced energy loss. In the coming ten years, the photonics World market will treble in size, reducing >10% the fuel consumption and CO2 emissions [1][2]. Energy saving will be much higher if all components are optimized, and optical-electrical-optical conversions minimized, by replacing semiconductor-based solutions with optical components.

This project aims to develop new materials for integrated optical devices, starting with passive organic-inorganic hybrid matrices and later focusing on composites with nonlinear optical properties, amplifying properties which will be combined to overcome propagation losses.

The flexibility of hybrids enables implementing 3D second-order nonlinearity via femtosecond laser irradiation. At UAVR organic-inorganic hybrids (di and triurea cross-linked poly(oxyethylene)/siloxane ormolytes) will be produced by sol-gel and self-directed assembly (Fig. 1a). Commercial nonlinear organic dyes and high-efficiency Ln3+ complexes and inorganic nanoparticles will be embedded in the hybrids for optical amplification in the visible/infrared spectral range, allowing the necessary combination of highly nonlinear materials and amplification to minimize losses. Materials will be characterised by X-ray diffraction and small-angle X-ray scattering, NMR, AFM, TEM, SEM, thermal analyses, vibrational, absorption and photoluminescence spectroscopies.

Inorganic nanoparticles offer robustness and stability towards optical excitation if excellent crystallinity and low levels of defects are achieved. Nanoparticles will be developed with a narrow size distribution through different synthesis routes. Low defect density and high crystallinity lanthanide (Ln3+)-doped efficient low phonon materials and mixed anions nanomaterials will be investigated, aiming to exploit high-emission cross section in the visible and the mid-infrared ranges. The nanomaterials will be dispersed in polymer and organic-inorganic hybrid matrices, enabling an original design (Fig 1b).

[1] Photonics Technologies and Markets for a Low Carbon Economy, European Commission Report (2010/0066)
[2] Adel A. M. Saleh ,Jane M. Simmons, All-Optical Networking – Evolution, Benefits, Challenges, and Future Vision, Proc of the IEEE, 100, 5, (2012), p. 1105

Fig 1. a) SEM and prototype photos of a Y-power coupler written by direct UV laser writing on a di-ureasils hybrid, scheme of a thermally-actuated Mach-Zehnder interferometer; b) Organic-inorganic composite matrix for amplification.

Goals of the PhD project

Organic-inorganic hybrids, such as di and triurea cross-linked poly(oxyethylene)/siloxane ormolytes (di- and tri-ureasils) will be prepared at UAVR by sol-gel and self-directed assembly. Commercial nonlinear organic dyes (e.g., DR1, DR13, Red17) and high-efficiency Ln3+ complexes and inorganic nanoparticles will be embedded in the hybrids. A refractive index contrast up to 10-1 will be obtained via Zr, Ti alkoxides addition. Materials will be characterised by X-ray diffraction and small-angle scattering, NMR, AFM, TEM, SEM, thermal analyses, vibrational, absorption and photoluminescence spectroscopies.

The French academic partner (UBX) will be responsible for the synthesis of inorganic materials, such as non-doped and Ln-doped niobates, low-phonon energy mixed anion material (oxysulfides, oxynitrides or oxyfluorite). Soft chemistry will be used to control nucleation and growth. The obtained particles will be dispersed in a polymer matrix at UAVR.

Materials provided by UAVR and UBX will be studied by bulk and confocal fluorescence spectroscopy, and correlative microscopy applied to relate optical and structural properties (NLO and luminescence) using multimodal spectroscopy at UBX.

Coriant and Telecom Institute are responsible for using the new materials to fabricate devices for the new generation of optical networks: (i) couplers, ring resonators filters, Mach-Zehnder interferometers, and (ii) non-linear electro-optic components and optical amplifiers.

Candidate profile

The candidate will have a master degree or equivalent obtained with a high ranking (above 14/20) with competencies in chemistry and materials science, a background in nanosciences and nanotechnology with specialization in optical spectroscopy. The candidate has to be motivated, curious and deeply involved in its research project. He/She will be able to run autonomously the syntheses, structure characterisation and luminescence experiments.

He/She will share time between the University of Aveiro (50%) and the University of Bordeaux (ICMCB) (50%). A few months will be dedicated to a collaboration project at Coriant industry.

Project Partners

The Cluster exploits the complementary expertise in nanoparticles processing, hybrid interfaces, devices fabrication, and linear and nonlinear optical characterization of:

CICECO-Aveiro Institute of Materials (UAVR) - hybrid matrices, undoped and Ln3+-doped passive and active device fabrication. Key People - Profs. Luis Carlos, Joao Rocha, Rute Ferreira

Institute for Condensed Matter Chemistry Bordeaux (ICMCB) (UBX) - inorganic nanoparticles, correlative/ multimodal microscopy, fs laser writing. Key People - Dr Veronique Jubera, Dr Thierry Cardinal

Coriant GmbH Munich (former Siemens Nokia Networks) - validation of optical devices with commercial equipment produced by the company for metro/core networks

Host Country (employment): Portugal

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