Fiber Optic Test Methods and Measurement Types

In order to assess the quality of fiber installations, sign off on the readiness of fiber optics for service activation, and ensure that fiber optic links continue to work stably, some basic fiber optic testing methods and tools must be used.

There are several important things to measure, evaluate and check:

1.Fiber end face detection

When coupling two fibers together, a key requirement is to ensure that light passes from fiber to fiber without excessive losses or back reflections. The remaining challenge is to keep the end faces free from contamination. A single particle mixed into the fiber core can cause serious insertion loss and back reflection, and even damage the equipment. Proactive fiber inspection is important to ensure a reliable fiber connection.

2. Fiber continuity test

When testing fiber optic cable networks, a visible laser light source attached to one end of the cable can be used to verify transmission to the other end. This type of fiber testing is only used to detect serious fiber defects such as breaks. You can also use a fiber continuity test to determine if the correct fiber cable is connected to the correct patch panel location.

3. Optical loss measurement

The most accurate way for a fiber optic tester to measure the total optical loss in a fiber is to inject a known level of light at one end and use an OLTS to measure the level of light at the other end. The difference between the source power level and the received power level is the loss. This method requires access to both ends of the fiber since the light source and power meter are connected at opposite ends of the link.

4. Optical power measurement

Power measurements are tests of the strength of the signal from the transmitter while the system is active or activated. The optical power meter will display the received optical power on its photodiode and can be connected directly to the output of the optical transmitter, or where the optical receiver is located on the fiber optic cable. Optical power can be measured in "dBm" units (absolute values), where "m" stands for 1 milliwatt and "dB" (used when setting reference levels) refers to decibels.

This additional capacity may be needed sooner than expected as 5G, the Internet of Things (IoT) and artificial intelligence accelerate consumption that is already growing significantly year over year. Not surprisingly, the fiber optic testing market is expected to grow at nearly 9% annually for the foreseeable future. To ensure this bright future, the continued development of fiber optic testing is key.