SAN FRANCISCO – Silicon Valley startup Flawless Photonics has produced more than 5 kilometers of ZBLAN on the International Space Station in two weeks.
It’s an achievement that eluded other companies that tried to produce the fluoride glass in microgravity.
For in-space manufacturing, Flawless Photonics’ accomplishment “is in a class by itself,” Lynn Harper, strategy lead for NASA ISS InSpace Production Applications, told SpaceNews. “They have successfully manufactured commercial lots of ZBLAN in space. They’ve done it repeatedly.”
Killer App
ZBLAN, an optical fiber prized for its transparency and widely used terrestrially in lasers and amplifiers, has long been considered a potential killer app for in-space manufacturing. If companies could produce fibers in microgravity with fewer imperfections than fibers produced on the ground, the thinking went, they could bring them to Earth and sell them at prices high enough to make the whole endeavor profitable.
Flawless Photonics’ “unprecedented results” are likely to prompt investigations into new types of glass that could be “very important for our defense industry and our national security,” said Rose Hernandez, director of InSpace Production Applications for the ISS National Lab. “Now they can tap into technologies that were not possible on Earth.”
Energy Savings
ZBLAN offers the promise of energy savings.
“The moon shot here is making undersea cables with ZBLAN,” said Michael Vestel, Flawless Photonics chief technology officer and vice president.
ZBLAN is far more transparent than silica, the fiber-optic glass in undersea communications cables. Improved transparency translates to less signal attenuation.
So, instead of having inline optical repeaters to boost the signal in submarine communications cables “every 40 or 50 kilometers, you could have them at distances of 10 or 100 times that,” said Vestel, who earned a PhD in materials science and engineering from the University of California, Berkeley. “Why does that matter? It turns out the power of those amplifiers consumes energy on the order of 1 percent to 1.5 percent of the entire global budget of energy.”
Return Flight
Samples of ZBLAN produced by Flawless Photonics are scheduled to return to Earth on a SpaceX’s Commercial Resupply Services flight in April. At that time, NASA and an independent third party will study the quality and composition of the optical fibers produced on ISS.
Whatever those evaluations determine, Hernandez said, it’s important to note that Flawless Photonics already has demonstrated the ability to manufacture ZBLAN in microgravity.
“As someone that has done product manufacturing for a long time, I see a product that needs verification,” Hernandez said. “But I already see the manufacturing that has been working for over a year and a half on the ground and now has been demonstrated on station.”
ESA and LSA Backing
The European Space Agency and Luxembourg Space Agency provided funding for Flawless Photonics’ machine for drawing optical fiber in space. The ISS National Laboratory paid for ISS transportation and installation in the Microgravity Science Glovebox.
ZBLAN is produced from a heated cylindrical preform with a glass core surrounded by cladding and coating. As the fiber is pulled, it thins out and eventually breaks. A key feature of Flawless Photonics’ microgravity machine is its ability to restart the process of pulling optical fiber after the fiber breaks.
“If you can’t restart every time it breaks, you’re never going to get to the point of being able to demonstrate process control,” Vestel said.
Next Steps
For Flawless Photonics, the next step is making preforms in space. NASA’s In Space Production Applications program is paying for a preform manufacturing experiment by Flawless Photonics, Australia’s University of Adelaide, Axiom Space and Visioneering Space.
“Making these preforms in space will allow us to even take more advantage of microgravity to continue to make better products,” Vestel said.
Twenty Flawless Photonics employees contributed to the firm’s in-space production of fiber optics. The company’s work is funded through a combination of private and government funding.
Through an AFWERX program, for example, Flawless Photonics is develop ZBLAN laser products produced terrestrially.
