This test will measure the loss of a fiber optic cable, singlemode or multimode, including connectors on each end individually - one at a time. For short cables, e.g. patchcords, with negligible fiber loss, the measured loss may be considered the loss of the connector mated to the reference connector. Reversing the cable tests the connector on the other end of the cable. The method shown is on the FOA "1 Page Standard" FOA2 which you may print or download and insert in your documentation. Patchcords may also be tested both ends at once using the cable plant test method shown above.
Equipment Needed To Perform This Test
1. Test source (#1) appropriate for the fiber being tested (Multimode: 850 and/or 1300nm LED, singlemode, 1310 and/or 1550 nm laser)
2. Optical power meter (#2) calibrated at the same wavelengths as the source output with adapters to mate to connector type on cable.
3. Launch reference cable (#3) that is the same fiber type and size as the cable plant and have connectors compatible to those on the cable.
4. Mating adapters compatible to connectors (#4)
5. Cleaning supplies
1. Turn on equipment and allow time to warm-up
2. Attach launch cable to source. This should remain connected to source for the duration of the test.
3. Clean all connectors and mating adapters.
4. Set “0 dB” reference using method shown above. Meter may be set to read “0 dB.”
5. Attach source reference cable and to the cable under test and make loss measurement.
6. Reverse cable and test again. This tests the connector on the other end of the cable.
Options For Testing With Different Connector Types Or Double-Ended
If the connector(s) on the cables to test are “plug and jack” type and/or are not compatible to the optical power meter for testing and/or reference, you cannot test single-ended. Use the Fiber Optic Cable Plant or FOA "1 Page Standard" FOA1 method with a 2 or 3 Cable Reference as appropriate. Results will include loss of connectors on both ends.
Reducing Measurement Uncertainty
1. Clean all connectors regularly before and while testing.
2. Use modal control on launch cable, e.g. small loop on singlemode fiber or mandrel wrap on multimode fiber.
3. Check “0 dB Reference” periodically during testing.
Record the following data to document your tests and keep copies for future reference:
1. Date of the test
2. Cable being tested and fiber identification
4. Test equipment used
5. Reference method
6. Test wavelength
7. Measured loss.
Also see the FOA YouTube Video on loss testing
Also see the FOA YouTube Video on optical power testing
FOA "1 Page Standard" FOA1 (cable plant testing)
FOA "1 Page Standard" FOA2 (patchcord testing)
Online FOA Reference
FOA Reference Guide to Fiber Optics( general) , Basics/Testing, Test Section
FOA Reference Guide to Fiber Optics, Chapter 8
FOA Reference Guide to Outside Plant Fiber Optics, Chapter 8
FOA YouTube Videos , with individual links as appropriate
This information is provided by The Fiber Optic Association, Inc. as a benefit to those interested in teaching, designing, manufacturing, selling, installing or using fiber optic communications systems or networks. It is intended to be used as an overview and/or basic guidelines and in no way should be considered to be complete or comprehensive. These guidelines are strictly the opinion of the FOA and the reader is expected to use them as a basis for learning, as a reference and for creating their own documentation, project specifications, etc. Those working with fiber optics in the classroom, laboratory or field should follow all safety rules carefully. The FOA assumes no liability for the use of any of this material.