Raman spectroscopy is a powerful materials analysis technique used for identification of molecules residing near the surface of a sample. It has been successfully used for a broad range of application areas such as material science, biology, medicine and pharmacology owing to its numerous advantages. A traditional Raman measurement system is a complex setup, whose usage is limited due to its bulky and expensive components. If it would be possible to achieve a miniature Raman spectroscopic system with affordable costs by using integrated optics and electronics technology, it could be utilized further in the aforementioned applications. The goal of this PhD study is to realize small-scale optical components, which could be building blocks of a hand-held Raman measurement system, by using integrated optics. For this purpose, three different integrated optical modules in the SiON material platform are proposed in this thesis: Out of plane light turning mirrors, prism spectrometers and polarization splitters. Integration of on-chip optics and electronics is an important aspect of realizing small scale Raman measurement devices. A highly efficient, quasi- TIR (total internal reflection) based 90° out of plane light turning mirror for hybrid flip-chip integration of SiON waveguides and CMOS-based photodiodes is proposed in this thesis. The mirror is defined at the interface between the optical structure and air by removal of Si from the substrate. A spectrometer is a crucial part of Raman measurement systems. Here, we propose an integrated optical prism spectrometer, which utilizes dispersion effects in slab waveguides with two different thicknesses of the guiding layer, and which are connected adiabatically via vertical tapers. The principle and design aspects of the device are presented in detail. A theoretical analysis for the optical effects in the adiabatic transitions is also given. Furthermore, design, fabrication and characterization of a partially optimized on-chip prism spectrometer, to be used for TE polarized light at a central wavelength of 850 nm, are described. The design, fabrication and characterization of an on-chip polarization splitter (for a wavelength of 850 nm) to be used in polarized Raman measurements are also considered in this thesis. For the polarization splitting a waveguiding trench, with adiabatic transitions, is used.
|Award date||31 Oct 2014|
|Place of Publication||Enschede|
|Publication status||Published - 31 Oct 2014|