Showing papers by "Kerstin Worhoff published in 2006"

Optimization of Low-Loss AL2O3 Waveguide Fabrication for Application in Active Integrated Optical Devices

Abstract: In this paper we will present the fabrication and properties of reactively co-sputtered $AL_{2}O_{3}$ layers, being a very promising host material for active integrated optics applications such as rare-earth ion doped laser devices. The process optimization towards a reactive co-sputtering process, which resulted in stable, target condition-independent deposition of $AL_{2}O_{3}$ with high optical quality will be discussed in detail. The loss value of as-deposited optical waveguides sputtered by the optimized process has been measured. The loss in the near infrared wavelength range was 0.3 dB/cm. Furthermore $AL_{2}O_{3}$ material hosts fabricated by sputtering techniques are compatible with Si-based integrated optical technology and allow for uniform deposition over a large substrate area.

Rare earth doped nanoparticles in organic and inorganic host materials for application in integrated optics

Abstract: The preparation and the optical properties of lanthanum fluoride (LaF3) nanoparticles doped with erbium and neodymium will be discussed. Organic and inorganic materials in the form of polymers and sol-gels were used to serve as the hosts for the inorganic nanoparticles, respectively. The organic host material has been synthesized such that it is photo-crosslinkable to facilitate straightforward multimode and monomode waveguide fabrication. Our focus will be on the optical properties of both the inorganic rare-earth doped nanoparticles and the host materials. The importance of the refractive indices of the particles and the host material and particle size on the optical scattering properties will be addressed. The optical transmission windows of the host materials do overlap with the absorption peaks of the erbium and neodymium in order to have efficient optical pumping, as well as with the spontaneous emission spectra of the rare earth metals for use as optical amplifiers around 1330nm and 1550nm. Furthermore, the improvement on the excited state lifetimes of the rare earths in the nanoparticles compared to the lifetimes of rare earths directly immersed in sol-gels will be presented.

Metal mask free dry-etching process for integrated optical devices applying highly photostabilized resist.

Abstract: Photostabilization is a widely used post lithographic resist treatment process, which allows to harden the resist profile in order to maintain critical dimensions and to increase selectivity in subsequent process steps such as reactive ion etching. In this paper we present the optimization of deep UV-curing of 0,3-3.3 μm thick positive resist profiles followed by heat treatment up to 280 °C. The effectiveness of this resist treatment allows for metal mask free reactive ion etching with selectivity up to 6 for silicon structures, thermal silicon oxide and silicon oxynitride. This procedure is demonstrated by the results obtained in etching of various integrated optical structures.