How do you draw optical fiber?

How to Draw Optical Fiber

Drawing optical fiber involves a sophisticated manufacturing process that transforms preform glass into thin, flexible fibers used for transmitting light signals. This process is crucial for creating the backbone of modern telecommunications. Here's a detailed explanation:

1. Preform Fabrication

The first step is creating a solid glass cylinder known as a preform. This is achieved through methods like Modified Chemical Vapor Deposition (MCVD), where gases are deposited inside a rotating silica tube, heated, and then fused to form a solid glass preform.

2. Loading the Preform

The preform is carefully loaded into the top of a vertical drawing tower. This tower can be several stories high, ensuring enough space for the fiber to be drawn out to its full length.

3. Heating

The upper part of the drawing tower houses a furnace that heats the preform to a temperature around 2000°C, making the glass soft enough to be drawn into a thin fiber.

4. Drawing the Fiber

As the preform softens, gravity helps to pull it down, starting the drawing process. The operator initiates and controls the drawing speed to ensure the fiber's diameter remains consistent. Modern draw towers are equipped with laser micrometers that continuously monitor and adjust the fiber's diameter.

5. Coating

Immediately after the fiber is drawn, it passes through a coating cup where it is coated with one or more layers of protective polymer. This coating is cured using ultraviolet light, making the fiber strong and flexible.

6. Winding

The finished fiber is then wound onto a spool. The winding process is carefully controlled to avoid introducing any defects or stress into the fiber.

The drawn optical fiber is now ready for further testing and eventual use in various applications, including telecommunications, medical devices, and sensors.