Abstract: Single-ended optical fiber sensors, for which the same fiber length serves as lead-in and lead- out paths of the optical signal, offer many practical advantages over dual-ended sensors (particularly in their installation and interconnection). However, and this is especially relevant to optical fiber strain gauges, high interfacial stresses can develop at the tip of the sensor when the host material is under load. This can result in debonding of the sensor and, consequently, the loss of the sensor's function. The tip region can also be the site of initial crack formation in the host material. Using a shear-lag model and FEM analysis, we show how the use of coatings with appropriate properties can reduce or eliminate these problems. This analysis brings to attention important properties of the glass/coating and coating/resin interfaces that need to be determined from experiments. The conclusions from this analysis are discussed in the context of the broader issue of sensor/host interaction and sensor life-performance. !3
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