Optical Time Domain Reflectometer. The fiber optic equivalent of a TDR. Locates breaks, splices, and connectors in fiber cables and measures signal loss.

Optical Time Domain Reflectometer. The fiber optic equivalent of a TDR. Locates breaks, splices, and connectors in fiber cables and measures signal loss.

• A. TDR
• B. OTDR
• C. Light Meter
• D. Cable Tester

Answer: (B)

The key idea is that an Optical Time Domain Reflectometer is the fiber-optic equivalent of a TDR. It sends a short pulse of light into the fiber and listens for reflections caused by changes along the fiber—breaks, splices, connectors, or bends create reflections. By analyzing when each reflection returns, the OTDR can determine the distance to the fault and, from the reflection's strength, estimate the amount of signal loss at that location. This creates a trace that shows exactly where along the fiber there are events and how much loss they introduce, which is essential for locating faults and verifying installation quality. A TDR is the electrical counterpart used on copper cables, not fiber, so the OTDR is the appropriate tool for fiber. A light meter merely measures end-to-end light level and can’t locate faults along the length, and a general cable tester doesn’t provide the detailed trace of events and losses along the fiber.

The key idea is that an Optical Time Domain Reflectometer is the fiber-optic equivalent of a TDR. It sends a short pulse of light into the fiber and listens for reflections caused by changes along the fiber—breaks, splices, connectors, or bends create reflections. By analyzing when each reflection returns, the OTDR can determine the distance to the fault and, from the reflection's strength, estimate the amount of signal loss at that location. This creates a trace that shows exactly where along the fiber there are events and how much loss they introduce, which is essential for locating faults and verifying installation quality. A TDR is the electrical counterpart used on copper cables, not fiber, so the OTDR is the appropriate tool for fiber. A light meter merely measures end-to-end light level and can’t locate faults along the length, and a general cable tester doesn’t provide the detailed trace of events and losses along the fiber.