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

Mahmoud A. Gaafar, Dirk Jalas, Liam O’Faolain, Juntao Li, Thomas F. Krauss, Alexander Yu. Petrov, Manfred Eich

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

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.
Original languageEnglish
Article number1447
Number of pages10
JournalNature Communications
Volume9
DOIs
Publication statusPublished - 13 Apr 2018

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