Novel methods for distributed optical fiber sensing

Fully-distributed optical-fiber sensing is a potentially powerful tool for a range of industrial and research applications. Most methods which have been studied hitherto suffer from inadequate spatial resolution, inadequate sensitivity, or both. New methods are being explored in order to overcome these deficiencies. These are primarily polarization-optical methods which rely on birefringent fiber. Both linear and nonlinear optical effects are utilized in backscatter and forward-scatter systems. The methods are described and the future assessed.