The FI-100 Fiber Identifier measures core power in a fiber optic cable. Fiber is inserted into the fiber adapters, and the clamping mechanism causes a macrobend to be impressed upon the fiber. Two photodiodes measure the small portion of light that is "spilled" out of the fiber.
The FI-100 is able to measure the direction of light travel and can positively identify fibers using 270 Hz, 1 kHz, or 2 kHz tone detect frequencies. Precision fiber adapters for each fiber size introduce the exact amount of mechanical bend in the fiber without causing excessive loss. Technicians can probe fibers to identify which are active before disconnecting. This prevents the disconnection of a fiber that is being used for a critical service. The precise fiber adapters also make the FI-100 well-suited for bend-insensitive fiber, Greenlee says.
Fiber tracing allows the technician to identify a fiber when a tone is injected into it with a complementary laser source. The other end of the fiber can be located without disconnecting each fiber in a pedestal or cabinet that houses multiple fibers.