Experior Photonics: Test Services for Fiber Optics

Optical Dropout Test

Optical Dropout Testing (Fiber Optic Circuit Discontinuities)

Optical circuit discontinuities (optical dropouts) can occur when testing passive and/or active fiber optic components under vibration and mechanical shock conditions. A document published by the TIA (Telecommunication Industry Association) describes the test procedure (document # is: TIA/EIA-455-32A, available for purchase at www.tiaonline.org or global.ihs.com).

Optical circuit discontinuity testing is typically performed during a vibration or mechanical shock test. Hereby a continuous wave optical signal is connected to the input of the fiber optic component under test and the output of the component is connected to a high speed optical receiver. The following picture shows the principle test setup for testing on a fiber optic cable assembly:

After performing an initial baseline (reference) measurement, the PC compares each measurement against the baseline measurement to determine the magnitude of the optical power drop. The PC counts the number of test points below the "threshold" to determine the duration of the dropout.

This setup is highly flexible and can be programmed to measure dropouts at any magnitude and time duration (limited by the speed of the A/D converter). Typical dropout parameters are:

1µs dropout duration at 0.5dB, 1dB, or 3dB dropout magnitude
10µs dropout duration at 0.5dB, 1dB, or 3dB dropout magnitude