Methods and Equipments for Measuring Fiber Optic Signals
Visual fault locators, connector inspection (using microscopes), light sources and power meters, optical-fiber identifiers, and OTDRs are five examples of methods and equipments that can be used to measure fiber optic signals for troubleshooting purposes.
Visual Fault Locator
- A visual fault locator or fiber tracer is used to inject visible light into a fiber optic cable to visually trace the cable from the transmitter to the receiver to check orientation and continuity.
- Continuity testing can be used to test if a terminated cable is damaged. The test is carried out by attaching the fiber cable to the fiber visual fault locator.
- If visible light can be seen at the other end, then the fiber cable is not damaged.
- To trace a fiber cable, the cable is connected to the equipment's output connector. The light output can be seen at the far end of the cable.
- This allows a particular fiber cable in a multifiber cable system to be easily identified.
- A visual fault locator costs as low as $42.46.
Connector Inspection (Microscope)
- A fiber inspection microscope allows fiber connectors to be safely inspected for contamination which can cause network outages and to confirm that fiber cleaning procedures are effective.
- Some microscopes allow the connector to be inspected from different angles, either by angle illumination or tilting of the connector.
- Fiber microscopes are usually fitted with protective infrared filters to reduce the risk associated with viewing live fiber cables.
- Some video inspection equipment do not have a direct optical path from the fiber cable to the user's eye.
- These equipments use a video signal path (similar to a camcorder viewfinder) which converts the optical image from the fiber cable to a high resolution, safe video image.
- A fiber inspection microscope costs as low as $143.
Light Source and Power Meter
- A light source and power meter is used to measure the optical power from a transmitter or receiver in order to determine power loss.
- A transmitter's optical power by attaching a fiber cable to the signal source while the power is measured at the far end.
- The optical power of a receiver is measured by disconnecting the fiber cable connected to the receiver receptacle while the output is measured with the meter.
- The loss reading is then compared to an estimated loss, known as a loss budget, which was calculated for the fiber link.
- A light source and power meter costs as low as $245.
- An optical-fiber identifier or a live fiber detector (or optical-fiber detector) is used to detect the presence or absence of optical transmissions in a fiber cable.
- It is a non-intrusive equipment which is used by clamping it to a fiber cable.
- It then measures several indicators including "traffic direction, presence (or absence) of modulation and, on some units, a core power reading".
- The measurements enable the user to quickly assess the status of the fiber network.
- An optical-fiber identifier costs as low as $913.08.
Optical Time Domain Reflectometer (OTDR)
- An OTDR injects optical pulses into a fiber cable and extracts light scattered or reflected back from different points along the length of the fiber cable.
- The equipment measures the strength of the returned pulses and is used to determine the quality of the optical fiber cable.
- An OTDR costs as low as $2037.50.