Fiber Optic Cable Testing Tools

with fiber optic cables, mismatch between cables coupled together will result in data loss
- occurs if the fiber cables:
  - are not properly aligned
  - are different sizes
  - have suffered damage
when a connector is installed on the end of fiber optic cables, a degree of signal loss occurs
- called insertion loss
- some of the lost light is reflected back down the cable
  - called back reflection, reflectance, or optical return loss (ORL)
- UPC and APC polishing reduce ORL reflections
- using APC to a non-APC port causes major insertion loss
- APC connectors are always colored green

Visual Fault Locator

A visual fault locator identifies the location of a break in a cable.

different models for short and long links
supplied with adapters for different connectors
shines visible light down the cable and glows brightly at the point where a cable is broke, excessively bent, or improperly spliced

dirt, dust, or grease in transmission path reduces signal strength
commonly occurs at a connector
connectors should be covered with a dust cap
connectors should be cleaned with a solvent designed for fiber optics
wet-to-dry method:
- applies a drop of solvent to a lint free cloth
- moves the connector from the wet drop across a dry part
contamination could be introduced when a cable is spliced
- clean splicing equipment