Is there glass in the fiber optic cable?

　　The core transmission part of the fiber optic cable is indeed made of glass, and the specific structure is as follows:

　　1. Fiber core

　　Material: High-purity silica (SiO2), a type of glass.

　　Function: As a transmission channel for optical signals, the refractive index is increased by doping germanium (GeO _ 2) to ensure that light propagates in the core.

　　2. Cladding

　　Material: Silicon dioxide (SiO2), but doped with fluorine to reduce the refractive index.

　　Function: Wrap the core and use the principle of total reflection to limit the light signal in the core to reduce leakage.

　　3. Coating layer

　　Material: acrylic, polyimide or metal (e.g. aluminum, copper).

　　Function: Protect optical fiber, enhance mechanical strength and durability, non-glass material.

　　summarize

　　The core and cladding of the fiber optic cable are made of glass (silica), which is the key to its efficient light transmission. The coating layer acts as an outer layer for protection, and other materials are used. Therefore, to answer the user's question: the part of the fiber optic cable that transmits light signals (the core and cladding) is indeed glass.