Reflection from a free carrier front via an intraband indirect photonic transition.

ABSTRACT: The reflection of light from moving boundaries is of interest both fundamentally and for applications in frequency conversion, but typically requires high pump power. By using a dispersion-engineered silicon photonic crystal waveguide, we are able to achieve a propagating free carrier front with only a moderate on-chip peak power of 6?W in a 6?ps-long pump pulse. We employ an intraband indirect photonic transition of a co-propagating probe, whereby the probe practically escapes from the front in the forward direction. This forward reflection has up to 35% efficiency and it is accompanied by a strong frequency upshift, which significantly exceeds that expected from the refractive index change and which is a function of group velocity, waveguide dispersion and pump power. Pump, probe and shifted probe all are around 1.5?µm wavelength which opens new possibilities for "on-chip" frequency manipulation and all-optical switching in optical telecommunications.

SUBMITTER: Gaafar MA 

PROVIDER: S-EPMC5899136 | biostudies-literature | 2018 Apr

REPOSITORIES: biostudies-literature