What is the first step to diagnose an isolated problem in a fiber-optic system?

The first step to diagnose an isolated problem in a fiber-optic system is to examine the fibers with the Optical Time-Domain Reflectometer (OTDR). This tool is critical for assessing the integrity of the fiber link, as it provides a visual representation of the fiber's condition. By sending pulses of light through the fiber and measuring the returns, the OTDR can identify issues such as breaks, bends, and splice losses, effectively pinpointing the location and nature of the fault.

By utilizing the OTDR at the beginning of the troubleshooting process, technicians can gather vital information about the status of the fiber, which informs subsequent actions. Identifying the specific location of a fault before checking connections or rebooting systems allows for a more targeted and efficient approach to resolving the issue, rather than starting with actions that may not address the root cause. This method emphasizes the importance of obtaining precise data before taking corrective measures.