  Hydrogenated amorphous silicon (a:Si-H) has recently been recognized as a
highly nonlinear CMOS compatible photonic platform. We experimentally
demonstrate the generation of a supercontinuum (SC) spanning over 500 nm in
a-Si:H photonic wire waveguide at telecommunication wavelengths using
femtosecond input pulse with energy lower than 5 pJ. Numerical modeling of
pulse propagation in the waveguide, based on the experimentally characterized
dispersion profile, shows that the supercontinuum is the result of soliton
fission and dispersive wave generation. It is demonstrated that the SC is
highly coherent and that the waveguides do not suffer from material degradation
under femtosecond pulse illumination. Finally, a direct comparison of SC
generation in c-Si and a-Si:H waveguides confirms the higher performances of
a-Si:H over c-Si for broadband low power SC generation at telecommunication
wavelengths.
