Optical fiber length is typically measured using a technique that involves timing how long it takes for light to travel through the fiber. Specifically, the VOLT utilizes a round-robin method to accurately determine the length of optical fiber cables.
How the Round-Robin Method Works
The round-robin method employed by the VOLT works by:
- Looping Back Fibers: Two optical fibers are looped back at one end of the fiber run. This means light is sent through one fiber, then immediately back through the other.
- Measuring Round Trip Time: The device measures the precise time it takes for a pulse of light to travel through both fibers – the "round trip."
- Converting Time to Distance: This time measurement is then converted into a distance using the speed of light within the fiber, typically expressed in kilometers.
- Calculating Single Fiber Length: The round trip distance is then divided by two to determine the length of a single fiber cable.
| Measurement Step | Description |
|---|---|
| 1. Fiber Looping | Two fibers are looped back at one end. |
| 2. Light Transmission | Light is sent through one fiber and then back through the other. |
| 3. Time Measurement | Time taken for the light to travel the round trip is measured. |
| 4. Conversion to Distance | Time is converted into distance using the speed of light in the fiber. |
| 5. Single Fiber Calculation | Round trip distance is divided by two to get the length of a single fiber. |
Practical Insights
- Accuracy: This method offers a highly accurate way to measure fiber length because it directly measures the time taken by light to travel the distance.
- No physical stretching: This non-invasive method doesn't require physically stretching or manipulating the fiber, ensuring no damage occurs.
- Automation: Modern testing equipment like the VOLT often automates the process, allowing for quick and reliable length measurements.
- Application: This method is used in various applications, including installation, maintenance, and troubleshooting of fiber optic networks.
By using a round-robin method, devices like the VOLT accurately measure the length of optical fibers by timing light pulses and converting those measurements into distance.
