Jürgen Kasberger, Bernhard Jakoby,
"Influence of Waveguide Material on Spectral Separation of a Fully Integrated IR – Absorption Sensor System"
: Tagungsband zur Informationstagung Mikroelektronik 08, Nummer 50, OVE, Seite(n) 29-33, 10-2008
Influence of Waveguide Material on Spectral Separation of a Fully Integrated IR – Absorption Sensor System
Sprache des Titels:
Tagungsband zur Informationstagung Mikroelektronik 08
As an alternative to commercially available IR-spectrometers, which are in general expensive and bulky laboratory measurement instruments, miniaturized spectrometers have been investigated by several authors in the recent years. However, these devices either require external sources and detectors and hence do not represent fully integrated optical sensor systems or suffer from lacking sensitivities. Since micromachining technology enables the integration of all system components, we propose a fully integrated absorption sensor based on IR absorption in the evanescent field region of an integrated waveguide. To cover the desired wavelength region utilization of thermally generated and detected IR radiation is mandatory. The absorption is determined at prescribed discrete wavelengths rather than measuring a broad IR absorption spectrum. Two grating couplers are employed to couple IR radiation into the waveguide and the attenuated IR radiation towards a thermal IR detector. The sensitivity of the entire sensor system is determined by both, an appropriately designed waveguide element and the efficiency of each of the grating couplers. In this contribution, we consider the influence of the waveguide material on the sensitivity of the waveguide absorption element as well as the spectral separation of the applied grating coupler.