Thermal trimming and tuning of hydrogenated amorphous silicon nano-photonic devices

Deposited silicon and, in particular, hydrogenated amorphous silicon forms an attractive alternative platform for realizing compact photonic integrated circuits. In this paper we report on trimming (toward lower wavelengths) and tuning (toward higher wavelengths) of photonic devices through a suitable thermal treatment. The former is achieved by a material density change, the latter through the thermo-optic effect. By using Fourier transform infrared spectroscopy, a change in the hydrogen content is identified as the source of the density change. A total wavelength tuning range of 24.6 nm is achievable, which can be used for compensating fabrication imperfections. c 2010 American Institute of Physics. [doi:10.1063/1.3479918]