Fiber splice loss measurement point

Optical loss is a measure of a fiber optic connector an important indicator of quality, there are several measurement methods can determine the optical loss of optical fiber connectors, such as the use of optical time domain reflectometer (OTDR) or splice connector loss assessment programs.

1. Fusion splice loss evaluation
Some welding machines use a fiber-optic imaging and measuring geometric parameters of the cross-section arranged in the system. Observed from two perpendicular directions through the optical fiber, computer processing and analysis of the images to determine cladding offset, core distortion, fiber diameter changes and other key parameters, use these parameters to evaluate the connection loss. It depends on the joints and loss of splice loss evaluation algorithm may obtain the true splice loss are considerable differences.

2. Using optical time domain reflectometer (OTDR)
Optical time domain reflectometer (OTDR: Optical Time Domain Reflectometer), also known as back-scattering instrument, the principle is: the light pulse to the optical fiber, due to scattering in fiber micro light, back light lateral, can be used when the base to observe the reflected light of the return. As the fiber mode field diameter affect its backscatter, so both sides of the fiber optic connector may have different backscatter, thus masking the true joint loss. If the connector from the loss measurements in both directions, and find the average of these two results, one-way OTDR measurements can eliminate the human factor errors. However, in most cases is the operator measuring splice loss from only one direction, the result is not very accurate, in fact, due to a mismatch of mode field diameter of the fiber loss caused by the intrinsic splice loss than 10 times their own.