SiOxNy / SiN Technology

For realising passive integrated optical circuits (waveguides, TE/TM filters, gratings, splitters etc.) the SiOxNy-technology is well suited.

The refractive index can be set between n = 1.46 (SiO2) and 2.01 (Si3N4) with an accuracy of < 0.001 and extremely low attenuation. The specific value of r.i. is controlled by the gas flow ratios, when depositing these layers by LPCVD or PECVD technologies.

SiOxNy allows for creating waveguides with low (<1%) medium (~1-5%), large (~5-15%), very large (15-35%) and extremely large (>35%) index contrasts. For datacom applications the currently often applied small contrasts are currently replaced by medium contrasts, as these waveguides go with reduced bend radii and therefore smaller devices. For IO sensing applications, most often extremely large contrasts are beneficial, as this goes with increased surface sensitivity exploiting the evanescent field. In between these two application fields, the large index contrast range is often applied for IO-spectroscopy.

With a newly patented LPCVD technology, we can produce very large contrast waveguides with minimal modal birefringence and very low channel attenuation (0.1 dB/cm at 1.5 micron).

SiOxNy is perfectly compatible with Si-technology. For example V-grooves for fiber to chip couplings can be made by KOH etching, or electrostatically activated waveguides can be made for fabricating switches (MOEMS; micro optoelectromechanical systems), but also activation by other active materials such as e.g. ZnO is applied.

Attenuation in dB/cm (indication)