NASA’ 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 several 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.
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.
And in 2014, OEwaves spun off a company called Strobe Inc. to develop Li-DAR 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.
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