Tech Briefs Magazine - March 2023 - 30

Electrical/Electronics
Serial Arrayed Waveguide Grating
An arrayed waveguide grating that splits up an optical signal into wavelength channels to
enable higher spectral resolution.
Goddard Space Flight Center, Green Belt, MD
D
ispersive optical elements are
important for many applications.
In bulk, free-space optics,
prisms, and gratings are often used.
In optical waveguides, particularly in
integrated photonics, arrayed waveguide
gratings (AWG) are most commonly
used. AWGs split an optical
signal into different wavelength
channels. Serial Arrayed Waveguide
Grating enables higher resolution
wavelength separation.
Traditional AWGs split the optical
signal into multiple parallel paths
each with a different path length.
This new approach creates the different
path lengths by splitting the signal
into essentially one long path in
which the different channels are periodically
split off the main path in the desired
fraction. This has the net result of
requiring much less space on-chip for
comparable optical path differences.
length between the paths. To design
this on a photonics chip requires significant
area. The serial AWG creates
a single path, equivalent to the longest
path in the parallel AWG and
split off fractions of the optical signal
at various points along the way to create
the equivalent path lengths. Serial
Arrayed Waveguide Grating re-uses
the same path instead of needing independent
parallel paths.
The technology has several applicaSerial
Arrayed Waveguide Grating enables higher resolution
wavelength separation. (Image: NASA)
In traditional AWG, there are multiple
parallel optical paths, each with a different
engineered path-length. For high
resolution, you want many different parallel
paths and large differences in path
tions including optical communications,
remote sensing/LiDAR, and
beam steering.
NASA is actively seeking licensees
to commercialize this technology.
Please contact NASA's Licensing
Concierge at Agency-Patent-Licensing@
mail.nasa.gov or call at 202-358-7432 to
initiate licensing discussions. For more
information, visit https://technology.
nasa.gov/patent/GSC-TOPS-302.
Health Monitoring with Skin-Like Electronics
New wearable electronics paired with artificial intelligence could transform screening
for health problems.
Argonne National Laboratory, Lemont, and University of Chicago, IL
F
lexible, wearable electronics could be
used for precision medical sensors attached
to the skin, designed to perform
health monitoring and diagnosis. Such a
skin-like device is being developed in a project
between the U.S. Department of Energy's
(DOE) Argonne National Laboratory
and the University of Chicago's Pritzker
School of Molecular Engineering (PME).
Leading the project is Sihong Wang, Assistant
Professor in UChicago PME with a
joint appointment in Argonne's Nanoscience
and Technology division.
Worn routinely, future wearable electronics
could potentially detect possible
emerging health problems such as heart
disease, cancer or multiple sclerosis,
even before obvious symptoms appear.
The device could also do a personalized
30
analysis of the tracked health data while
minimizing the need for its wireless
transmission.
Such a device would need to collect
and process a vast amount of data, well
above what even the best smartwatches
can do today. And it would have to do
this data crunching with very low power
consumption in a very tiny space.
To address that need, the team called
upon neuromorphic computing. This
AI technology mimics operation of the
brain by training on past data sets and
learning from experience. Its advantages
include compatibility with stretchable
material, lower energy consumption,
and faster speed than other types of AI.
The other major challenge the team
faced was integrating the electronics
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into a skin-like stretchable material. The
key material in any electronic device is
a semiconductor. In current rigid electronics
used in cell phones and computers,
this is normally a solid silicon chip.
Stretchable electronics require that the
semiconductor be a highly flexible material
that is still able to conduct electricity.
The team's skin-like neuromorphic
" chip " consists of a thin film of a plastic
semiconductor combined with stretchable
gold nanowire electrodes. Even
when stretched to twice its normal size,
their device functioned as planned without
formation of any cracks.
As one test, the team built an AI device
and trained it to distinguish healthy electrocardiogram
(ECG) signals from four
different signals indicating health probTech
Briefs, March 2023
https://technology.nasa.gov/patent/GSC-TOPS-302 http://www.techbriefs.com
Tech Briefs Magazine - March 2023

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