`Optical fiber manufacturing (Corning)`

Silicon tetrachloride flame-sprayed on a starting rod; graded composition for graded index of refraction; drawn into miles of fiber. Drying step removes moisture (hydroxide formation degrades optical properties).

The next lecture I give is on Tuesday, and I didn't get all the way through the glass stuff I had thought about this morning. If you want to go to YouTube or Corning, they have some videos on making optical glass fibers. I decided optical glass fibers aren't a structural material, but it's a wonderful story. They take silicon tetrachloride gas, because it's so pure, and they flame-spray a starting rod, and they build up something that's like an inch or two in diameter. They grade the composition as they do it, so they get a graded index of refraction. Then they draw it — it's called drawing the glass — they take this precursor and they draw miles and miles of optical fiber.