Fiber optic cables have varying sizes, but the core optical fiber itself is very thin. Here's a breakdown of their dimensions, referencing information from Quora:
Fiber Optic Cable Dimensions:
| Component | Diameter | Description |
|---|---|---|
| Core Optical Fiber | ~125 microns | The actual glass or plastic fiber that carries the light signals. |
| Coated Fiber | 0.25 to 0.5 mm | The fiber with its protective coating, which safeguards against mechanical damage. |
Key Points to Understand:
- Microns vs. Millimeters: A micron (µm) is one-millionth of a meter. There are 1000 microns in a millimeter. So, 125 microns is 0.125 mm.
- Cladding: The 125-micron diameter refers to the cladding. Cladding is the outer layer of glass that surrounds the core of the fiber, which is even smaller.
- Coating: The coating, which is a layer of plastic, increases the overall diameter of the fiber to between 0.25 to 0.5 mm (or 250 to 500 microns).
- Cable vs. Fiber: It's important to distinguish between the fiber itself and the complete cable. The cable is much larger and includes additional layers such as strength members and jacketing to protect the fiber from the environment and physical stress.
Why are they so thin?
- Fiber optics use light to carry information. Thinner fibers allow for efficient light transmission and are flexible, making them easier to work with.
- The thin core, surrounded by a slightly larger cladding, creates a boundary that allows for total internal reflection, a process which guides light along the fiber's length, preventing loss of signal.
- The thin fiber allows for more fibers to be packed within a cable, which allows for greater bandwidth in communication systems.
In summary:
While the coated fiber might be 0.25 to 0.5 mm in diameter, the core optical fiber, including the cladding, is around 125 microns in diameter, making the core itself even smaller. The larger dimensions we often see are due to protective layers around the fiber.
