Amorphous silicon (a-Si) is considered as one of the potential materials for multi-layer photonics due its high refractive index, linear and non-linear optical properties. This makes a-Si integration compatible with the Silicon-on-Insulator (SOI) photonics by increasing circuit density at each optical device layer. However, the high absorption loss of a-Si would require hydrogenation to passivate the dangling bonds for low loss optical waveguide interconnects and coupling of light between optical layers. Without an efficient passivation process, optical loss per layer would be too high for a viable multi-layer photonic platform. Therefore, we have developed a low temperature process hydrogenated a-Si (a- Si:H) with Hot-Wire Chemical Vapour Deposition (HWCVD) method that is compatible with back-end-of-the-line (BEOL) integration with active photonic or electronic layers. This work describes the experimental control of deposition temperature to achieve low loss a-Si:H waveguiding layer and the inter-layer waveguide coupling structures. Our latest results show a-Si:H deposited at 230 oC has the lowest propagation loss of 0.7 dB/cm for a sub-micron ridge waveguide at 1550 nm wavelength and 45 dB cross-talk isolation between two waveguides separated by 1 μm of SiO2 layer.
In recent years, we have presented results on the development of a variety of silicon photonic devices such as erasable gratings and directional couplers, tunable resonators and Mach-Zehnder interferometers, and programmable photonic circuits using germanium ion implantation and localised laser annealing. In this paper we have carried out experiments to analyse a series of devices that can be fabricated using the same technology, particularly silicon-on-insulator racetrack resonators which are very sensitive to fabrication imperfections. Simulation and experimental results revealed the ability to permanently optimise the coupling efficiency of these structures by selective localised laser annealing.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.