Photonics Research Group publishes a paper in Nature Photonics about mid-infrared spectral translation in silicon waveguides
In this Nature Photonics publication1 (Nature Photonics 6, 667–671 (2012)) researchers from the Photonics Research Group show that by using a nonlinear optical process in silicon optical waveguides, mid-infrared optical signals can efficiently be up-converted to the near-infrared wavelength range, where they can be detected using well-developed, high-sensitivity photodetectors. This is a stepping-stone towards the development of high-sensitivity mid-infrared spectroscopic sensing systems fully integrated on a silicon waveguide circuit.
applications cover the full wavelength range from ultraviolet over the visible
into the near-infrared, mid-infrared and far-infrared, the sensitive detection
of this light becomes more difficult to achieve when the optical wavelength
becomes longer. This limits the achievable sensitivity of sensor systems based
on mid-infrared light beams interrogating a sample. In this paper we show that
weak mid-infrared signals can efficiently be up-converted to a shorter
wavelength by means of a nonlinear optical process (namely four-wave mixing) in
a silicon optical waveguide2. This allows detecting the mid-infrared
signals with very well developed high-sensitivity, high-speed photodetectors
developed for telecommunication applications. This demonstration is a
stepping-stone towards the realization of silicon optical chips implementing
very sensitive optical sensing systems in the mid-infrared using the existing
telecommunication technology base for the detection of the mid-infrared signal.
This result was obtained in the framework of two European Research Council
grants in the Photonics Research Group (Department of Information Technology) at
Ghent University: MIRACLE (prof. Günther Roelkens) and InSpectra (prof. Roel
Baets), and was obtained through a collaboration with Columbia University and
IBM TJ Watson Research Center in New York, USA.
2 fabricated through the silicon multi-project wafer service ePIXfab