I am doing research on the fiber optics components reliability issues. I taking part in two research projects. One is Analysis of Proof Testing for Optical Fiber. Prooftesting optical fiber is being used to guarantee a minimum strength of the proof test stress level. But it has been shown in literature that theoretically the minimum strength of fibers that pass the prooftest could be much less than the prooftest stress level, and the minimum post-proof strength is determined only by the unloading rate during the prooftest. This theoretical conclusion is not consistent with historical field data that no failure below proof stress has been recorded. I am trying to resolve this discrepancy from a probability point of view. A Weibull distribution of pre-proof strength is assumed, as well as the power law subcritical crack growth model. The post-proof strength distribution has been derived. Fig 1 is an example of my analytical results. It shows that the prooftest cuts off the pre-proof fiber strength clearly, but the resulting cutoff of post-proof strength distribution is not so straight. It is possible that post-proof strength is less than the proof stress level. But the probability turns out to be very small, in order of 10-5. So it’s pronounced that theoretically the post-proof strength could be less than the proof stress, practically this will not happen. The influence of prooftest parameters has also been discussed in this work. The other project I’ve been involved in is to characterize the fiber and epoxy stresses in PC optic connectors. We are using Fiber Bragg Grating as our stress sensors.

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Last modified: February 23, 2002