Besides protection, what additional function must the coating on an optical fiber perform?

The coating on an optical fiber is crucial not only for protection against physical damage and environmental factors, but it also must be able to function effectively over a wide temperature range. This is important because optical fibers may be exposed to varying temperatures throughout their installation and operation. If the coating fails to maintain its integrity or performance in extreme conditions, it could lead to degradation in the fiber's performance.

The ability of the coating to withstand these temperature variations ensures the reliability of signal transmission in different environments, whether in outdoor settings exposed to the elements or in controlled indoor settings where conditions may still fluctuate. Therefore, a coating that can maintain its protective qualities and functional characteristics over a wide temperature range is essential for the overall performance and longevity of the optical fiber.

While other factors, such as mechanical strength and aesthetics, might be considered, they do not override the critical need for temperature resilience in ensuring the fiber’s operational reliability.