Method for Measuring Optical Fiber Strain Applied to Determine Strain in Fusion Splice Protectors

A method to measure strain in optical fibers using modal interference is proposed. The method is used to investigate fiber stress when the fiber is covered by a heat shrink sleeve, a so-called splice protector commonly used to protect fusion splices. The results are compared with a model based on the thermal expansion properties of a standard heat shrink sleeve. It is shown that for temperature ranges normally used for optical fiber components, the spliced fiber will be under compression when covered by the protector.