Contributed by C. David Chaffee, Chaffee Fiber Optics
In a rare historical moment, Robert Maurer, Peter Schulz and Don Keck, the team that originally made the first commerciable optical fibers in the world while at Corning, have been reunited at the show this week. I was humbled to have a few moments to talk to them about their revolutionary discovery, which has created a multi-billion dollar industry and changed the face of communications.
It was clear that Maurer was the leader, a man who began to look into low-loss optical fibers in 1966 when the famouns Kao/Hockham paper was first published. "Things went pretty slow at first and it was clear I was going to need some help," says Maurer. "When I got these two guys to join me, things picked up."
Maurer and the team had no doubt what their mission was, and that telephone companies were running out of capacity. "Everybody knew there were constraints and that optical communications was a possible solution," Keck recalls.
Schulz, who will fully detail the discovery tomorrow night at a special event honoring Charles Kao, remembers that it was actually a visit by a Corning official to the British Ministry of Defence that made the possibility clear. "We were really told very specifically by that Ministry of Defence team to try to make single-mode fiber with about a five micron core and to have attenuations of less than 20 dBs per kilometer. So our goal was to go from that to actually succeed."
None of the three would say they knew they were going to succeed from the outset. "We wanted to try," recalls Maurer. "I don't think anything can be done until it is."
Maurer led the group, Schulz was working with materials, Keck was working with measurements. The fibers were being drawn in the development group."We were really seeing if but using fused silica and putting additives into fused silica to change the refractive index," recalls Maurer. "We were trying to see if that method could lead to an actual fiber. We had no idea whether it could or not."
"Together we kept going forward as we ran our experiments," recalls Schulz.
"We were looking for other glasses that were high in silica at that time," says Maurer.
"Bob always told us if we only do things like everyone else, all you can hope for is a tie," says Keck. "We were looking for a win." Therefore, the team decided to take a contrarian approach. "The contrarian approach was to put an impurity in the glass to raise the refractive index--not enough impurity to impair anythiing. Then you put the silica around it. Ultimately it came to that sort of break that led to our winning solution. But it wasn't exactly like falling off a log."
Not hardly. In fact the early fibers the team worked on had losses of tens of thousands of dBs, recalls Schulz, "higher than the best conventional optical glasses. We worked away at it, picked away at it, and found what the mechanisms were and slowly but surely eliminated the losses until finally after four years of work we ended up finding what worked."
There were actually two eureka moments. The first involved Keck, who had just heated a fiber late in the afternoon in 1970, took the fiber out of the furnace and had a laser beam hooked up. "The laser beam hit the core of the fiber and I was blinded by the light. It was a big blaze of helium neon light and then we went through the measurements and had met our goal," recalls Keck.
Schulz says Eureka II came two years later when the team was struggling to bring the fiber to commercial mode. In the meantime it kept working to try to find other additives to improve it. "In 1972 we made a germania doped silica core fiber. This was multimode. This germania doped fiber we were pulling it and the light kep blazing through the fiber. First loss measurement was four dB per kilometer. We knew we had something."
The team stayed engaged thereafter and got support from idfferent teams and the effort got bigger until literally thousands of researchers were involved
While germania doping was a key, it took many, many years before the first long-haul fiber was used, Keck recalls. In fact, it was 12 years after that initial discovery."When you revolutionize the world, young scientists don't understand how long it takes."
Other problems were knocked out one by one through the expanded groups of researchers at Corning and elsewhere. LEDs were used before problems could be overcome with lasers, including coupling. Corning joined with Siemens to create a cable company known as Siecor. General Cable became involved.
The rest, as they say, is history.
Maurer's advice to young scientists? "Don't be afraid. Go ahead and try it." Adds Keck: "Have a dream. Find somebody to share it with."