Embedded Optical Fiber Ice Stress Gauge. Phase 1

摘要

Direct observations of ice stress provide an important constraint on models ofthe behavior of the Arctic ice cover. Present means of observing these stresses have been limited by gauge sensitivity, bandwidth, thermal response, and nonlinear ice behavior. This report describes a Phase I feasibility study of a new type of ice stress gauge based on an optical fiber embedded in a flat panel. The sensing mechanism used in this gauge is stress-induced birefringence, which causes a linear phase change in polarized light in the optical fiber. Tests of a prototype gauge embedded in a block of ice showed that the gauge has the sensitivity and range required for observations of sea-ice stress. The thermal sensitivity and drift characteristics of the gauge were also shown to be small. A design for a compact, low-power gauge with a diode laser light source and integrated opto-electronic polarization analyzer is also provided. This gauge would be suitable for remote field observations of the state of biaxial stress in the Arctic ice pack at a cost that is comparable to existing gauge technology.