Digital Gain Control Optical Fiber Route Security Monitoring is a sensing approach that uses software-driven gain regulation within a distributed fiber-optic vibration sensor to achieve uniform detection sensitivity across all branches of a passive optical network. By digitally adjusting amplification levels for each route segment, the system eliminates sensitivity variation caused by differing fiber lengths and splitter losses, enabling consistent, low-cost intrusion and disturbance detection across the entire network route without dedicated per-branch hardware.