A Level Physics Practice Exam

Why do optical fibers use a cladding?

1. To protect the core and enhance signal strength

2. To increase the temperature resistance

3. To allow more light through the core

4. To provide insulation against electrical interference

The correct answer is: To protect the core and enhance signal strength

Optical fibers use a cladding primarily to protect the core and enhance signal strength. The core of the optical fiber is where the light signal travels, and it must be surrounded by a cladding material that has a lower refractive index than the core. This setup is crucial for achieving total internal reflection, which is what allows light to be guided along the fiber with minimal loss. The cladding also provides physical protection to the core from damage and environmental factors, ensuring safer and more reliable data transmission. The design also prevents light from escaping the core, effectively enhancing the strength of the transmitted signal over long distances. By maintaining the integrity of the light signal within the core and minimizing signal loss, the cladding serves as an essential component in the performance of optical fibers.