Paul Steenson

Tellurite glass thin films on silica and polymer using UV (193 nm) pulsed laser ablation

Erbium-doped tellurite glass thin films were deposited using excimer (193 nm) laser ablation onto two different types of substrates: silica and polymer-coated silica for engineering optical integrated active–passive devices. The deposition conditions were optimized for both substrates in order to produce high-quality rare-earth (Er3+) ion-doped glass thin films with low propagation loss. The optical and spectroscopic properties of the deposited films, namely transmittance, fluorescence, lifetime as well as refractive indices at 633 nm were measured and analysed in detail.

Active glass–polymer superlattice structure for photonic integration

We propose an all-laser processing approach allowing controlled growth of organic-inorganic superlattice structures of rare-earth ion doped tellurium-oxide-based glass and optically transparent polydimethyl siloxane (PDMS) polymer; the purpose of which is to illustrate the structural and thermal compatibility of chemically dissimilar materials at the nanometer scale. Superlattice films with interlayer thicknesses as low as 2 nm were grown using pulsed laser deposition (PLD) at low temperatures (100 °C). Planar waveguides were successfully patterned by femtosecond-laser micro-machining for light propagation and efficient Er(3+)-ion amplified spontaneous emission (ASE). The proposed approach to achieve polymer-glass integration will allow the fabrication of efficient and durable polymer optical amplifiers and lossless photonic devices. The all-laser processing approach, discussed further in this paper, permits the growth of films of a multitude of chemically complex and dissimilar materials for a range of optical, thermal, mechanical and biological functions, which otherwise are impossible to integrate via conventional materials processing techniques.

Antipodal finline-to-microstrip transition for operation in the Ka band

An antipodal finline to microstrip transition for operation in the Ka Band (26.5-40 GHz) has been designed and characterised. Back to back transitions fabricated on soft substrates have been measured and simulated to verify their behaviour. Various configurations are implemented and a practical method to improve the design is used.

Glass–polymer superlattice for integrated optics

Abstract. Glass and polymer interstacked superlattice like nanolayers were fabricated by nanosecond-pulsed laser deposition with a 193-nm-ultraviolet laser. The individual layer thickness of this highly transparent thin film could be scaled down to 2 nm, proving a near atomic scale deposition of complex multilayered optical and electronic materials. The layers were selectively doped with Er3+ and Eu3+ ions, making it optically active and targeted for integrated sensor application.

Ultrafast laser plasma doping of Er 3+ ions in silica-on-silicon for optical waveguiding applications

An ultrafast laser plasma doping (ULPD) technique is used for high concentration doping of erbium ions into silica-on-silicon substrate. The method uses a femtosecond laser to ablate material from TeO2-ZnO-Na2O-Er2O3 (Er-TZN) target glass. The laser-generated plasma modifies the silica network, producing a high-index-contrast optical layer suited to the production of on-chip integrated optical circuits. Cross-sectional analysis using scanning electron microscope with energy dispersive x-ray spectroscopy revealed homogeneous intermixing of the host silica with Er-TZN, which is unique to ULPD. The highly doped layer exhibits spectroscopic characteristics of erbium with photoluminescence lifetimes from 10.79 to 14.07 ms.

Multi-ion diffusion in silica glass using femtosecond pulsed laser deposition

We demonstrate simultaneous implantation of Tellurium, Zinc, Sodium and Erbium ions in silica glass via fs-PLD. 1.3μm deep uniform diffusion with Δnmax of 0.169 was produced. Process is explained using existing models with experimental verification.

Platform manufacturing technique for next generation integrated photonic components

Innovation in integrated photonics and associated fields is imperative with looming bottlenecks in the existing internet infrastructure due to rapidly increasing demand, across society and industry, for greater bandwidth and data access. A priority in this field is the development of a monolithic photonic integrated circuit (PIC), simplifying the design, manufacture and material requirements of current devices, with reduced cost, power and footprints. Furthermore, an improved efficiency and performance is highly sought after as this market anticipates explosive growth. Typically the key components are often made through disparate methods, and then packaged together for a final device. This creates an exciting opportunity for a novel platform technology to overcome such limitations and enhance existing capabilities while opening up new frontiers in device design and complexity.

Femtosecond laser assisted multi-ion implantation in dielectrics

We report the simultaneous implantation of metal ions namely Te4+, Zn2+ and Na+ along with the rare-earth ion Er3+ using a femtosecond laser ablation and deposition process. Planar waveguide structures with 1.3 μm deep uniform diffusion with a maximum refractive index change (Δnmax) of 0.169 was produced in silica. This novel process will be explained using existing models with experimental verification. It has a potential to produce new materials and structures which are otherwise impossible to achieve via conventional glass and thin-film fabrication techniques. The unique possibility of diffusing rare earth ions opens new realm of photonic devices engineering.

Biomimetically reinforced transparent nanostructures fabricated by pulsed laser deposition

We have recently developed a new concept of glass and polymer superlattice structures that has superior optical and mechanical properties arising from atomic scale engineering approach. The interlayers of glass and polymer can have thickness as low as 2 nm and the structures can be grown on polymer or glass substrates by pulsed laser deposition technology. A biomimetic approach was carried out to optimise the reinforcement via replicated brick and mortar and gneiss rock structures. Discrete element method and nanoindentation methods were carried out to optimize the performance of such structures.

Femtosecond laser micromachining of tellurite thin film waveguides

Er:Yb:Ce doped phosphate modified tellurite thin films were produced by pulsed laser deposition. Femtosecond laser micromachining technique was used to pattern ridge waveguides on to the film surface. A series of experiments were carried out to optimize the thin film formation and also to pattern waveguides on to its surface with varying environmental and fluence conditions. The optimum waveguide was characterized in its passive and active regimes to ensure its operation at the C+L telecommunication band. The waveguides will be primarily used to amplification purposes for signal wavelengths ranging from 1520 nm – 1620 nm.