Tech Briefs Magazine - June 2022 - 56

SPINOFF
N
ASA' Deep Space Network
(DSN), a sort of GPS system
for space, relies on atomic
clocks for extreme accuracy.
Any modern navigation system
must accurately time radio signals
to triangulate a location.
But the need for accuracy is
even higher in space, where
great distances can compound
even tiny errors.
Advances made by Lute
Maleki, former researcher at
NASA's Jet Propulsion Laboratory
in Pasadena, CA, and his
JPL colleagues for space have
now led to some of the world's
most refined lasers and oscillators
for applications like communications,
range finders for self-driving cars, and
emerging fields like quantum computing.
In the 1980s, as he worked to improve
atomic clock technology for the DSN,
Maleki established what became known
as JPL's Quantum Sciences and Technologies
group to develop new capabilities
using the quantum physics that govern
the most elementary particles, such as
photons or the vibrating atoms in a
clock. The team developed a better,
more affordable type of atomic clock
and also, for the first time, sent atomic
clock signals through fiber-optic cables
to antennas almost 20 miles away.
In the early 1990s, Maleki and another
member of his lab ended up inventing a
new type of oscillator. " He had a stability
problem he couldn't solve, and I told
him to turn it into an oscillator to solve
it, and we invented the optoelectronic
oscillator, " Maleki said.
Oscillators are crucial not only for
timekeeping but also for communications,
where they let two or more devices
agree on a precise frequency at which to
send and receive information. While all
previous oscillators had used an electric
current to generate their vibration, this
one used laser light. The optoelectronic
oscillator has since become critical to sev56
NASA's
Deep Space Network uses atomic clocks to provide accurate spacecraft
navigation at great distances. A team at the Jet Propulsion Laboratory that
improved that technology developed new capabilities using quantum physics,
which are now part of the basis for OEwaves' laser technology. (Image: NASA)
eral applications, such as radar, space engineering,
and wireless communications.
To ensure a constant frequency, however,
the oscillator needs a resonator. At
the time, this usually was an optical fiber
that could carry an output signal over a
good distance - ideally a mile or so -
and circulate it back, allowing the system
to keep track of its own output frequency
and cancel out noise, Maleki explained.
It made for a bulky system.
This led to his second foundational invention:
the use of a whispering gallery
mode optical resonator. At the time,
NASA had little use for it, but Maleki was
confident there was a market.
He founded OEwaves (the OE stands
for optoelectronic) in 1999 with about
30 patents from his team's NASA work,
licensed through the California Institute
of Technology, which manages JPL.
Spinoff is NASA's annual publication featuring
successfully commercialized NASA technology. This
commercialization has contributed to the development
of products and services in the fields of health and
medicine, consumer goods, transportation, public safety,
computer technology, and environmental resources.
Next-Generation High-Performance Lasers
JPL's inventions improve lasers and oscillators for autonomous vehicles, next-generation
communications, and quantum computing.
The company took a while to
find its footing in a changing
technology landscape, but its
products, which include the
lowest-noise semiconductor lasers
available, have found new
markets opening up in recent
years. One is in " smart structures, "
a concept that has existed
for decades but is beginning
to be put into practice, especially
in Asia. Fiber-optic sensors
embedded in buildings,
bridges, railroads, and other
structures can sense stress or
deformation, but this requires
low-noise lasers to reveal tiny
variations in wavelength.
Maleki said he also expects increased
demand in the cellphone and communications
markets, as they move toward
higher frequencies, which carry information
more efficiently but require extremely
high fidelity.
Quantum technology allows OEwaves to produce
extremely low-noise, low-loss optoelectrical oscillators
the size of a penny. These enable tiny, efficient,
high-fidelity devices like the ultra-narrow-linewidth
laser above. (Image: OEwaves)
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And in 2014, OEwaves spun off a company
called Strobe Inc. to develop LiDAR
technology for self-driving cars. A
LiDAR system uses reflected laser signals
to build a three-dimensional map of its
surroundings, which many autonomous
vehicle companies regard as an enabling
technology. GM subsidiary Cruise Automation
purchased Strobe in 2017.
Maleki said the same technology that
began at JPL allowed Strobe to develop
small, efficient LiDAR systems that were
able to rapidly change frequency - a
technique called " chirping " - using
only the resonator. Chirping helps to
measure both the distance and speed of
surrounding objects. And the whole system
could be put on a photonic integrated
circuit, further reducing costs.
Several universities and companies are
also purchasing the laser components
to research future quantum devices for
communications, computing, and other
applications.
For more information visit https://spinoff.
nasa.gov/Lasers-Make-Waves.
Tech Briefs, June 2022
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https://spinoff.nasa.gov/Lasers-Make-Waves http://www.techbriefs.com http://info.hotims.com/82322-850
Tech Briefs Magazine - June 2022

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