| The image to the right is a photograph of a step-index
fiber, shown next to the tip of a sewing needle. This particular
fiber is fairly large by modern standards, but it provides a nice example
of the different layers in an optical fiber. The core
of the fiber is the 62 μm-thick clear layer exposed at the right end of
the fiber. The 125 μm-thick clear layer that comes next is the cladding.
The next layer is a white protective coating. The hair-like insulator
allows the fiber to move along its axis, preventing breakage as the fiber
is bent and coiled. The outer orange coating protects the fiber from
environmental effects like moisture. (Note that a solid cladding (instead
of air) makes it easier to add these protective layers.) To see a larger image in a new
browser window, click on the picture to the right. |
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