technology LEDs
rhombus4
Development of compact fibre-optic OCT diagnostic tools based on III-V
quantum dot superluminescent diode sources has been undertaken by
colleagues at the technical University of Denmark and the University of Cardiff.
Two major markets exist within dermatology and ophthalmology, for which high
power and broad bandwidth sources can give unprecedented enhancement in
the ability to resolve the structural morphology of human tissue
Figure 3: Fibre
coupled
superluminesce
nt diode
module
developed by
Alcatel-Thales
III-V lab with
project partners
Development of compact fibre-optic OCT diagnostic tools
based on III-V quantum dot superluminescent diode
sources has been undertaken by colleagues at the
technical University of Denmark and the University of
Cardiff. Two major markets exist within dermatology and
ophthalmology, for which high power and broad
bandwidth sources can give unprecedented enhancement
in the ability to resolve the structural morphology of
human tissue.
In one such example, a 3D OCT image of normal human
retina, made up of 512 individual cross-sectional scans is
shown right, together with that of a single scan below.
The image shows the fovea (to the right), peripheral parts widely sweeping sources need to be developed.
of the optic disc (to the left) and has good depth Furthermore the benefits of multispectral imaging are now
penetration into the retina as a consequence of the being realised by imaging with a linear array or even full
1060nm centre wavelength of the source. 2D cameras. So as the application moves on, perhaps the
simple superluminescent diode has had its day already.
So what next for OCT? The medical advances are clear: However broadband gain materials, such as quantum dots
in the hands of qualified medical clinicians, the technique will play an important role in future devices for this
is already playing a role in early-state cancer diagnosis in application.
skin and in the monitoring of ocular diseases that are the
world’s leading causes of blindness. But the technology
does not stand still and neither do the source With thanks to project partners Peter Andersen,
requirements. Attention is now turning to high speed OCT Wolfgang Drexler and Michel Krakowski. Interested
scanning performed by a tuneable laser source rather researchers are encouraged to visit the website
than the movement of an interferometer mirror. Low cost, http://www.nano-ub-sources.org for further information.
36 www.compoundsemiconductor.net November / December 2009
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