In optical wave guides, the optical cladding or cladding glass is the light-reflecting layer surrounding the inner fused silica glass. In optical fibers made of fused silica, the All Glass Fibers( AGF) or Silica Clad Silica( SCS), the inner glass is the core glass. It is surrounded by cladding glass, which is also made of quartz glass.
The core glass and the cladding glass have different refractive indices. They are mechanically inseparable. In addition to the classic optical fiber with core glass and cladding glass, there is also the double clad fiber( DCF), an optical fiber with a core glass and two cladding glasses.
In hybrid optical fibers such as the PCF fiber, Plastic Clad Fiber (PCF), or the HPCF fiber, Hard Polymer Clad Fiber (HPCF), the optical cladding is made of plastic and is not firmly fused to the optical core. In the case of the pure plastic fiber, the polymer fiber, the core material and cladding material are made of plastic.