IR sensing by fiber-optic speckle based interferometer

Abstract

In the previous papers we presented a speckle-based fiber optic method for registration of low intensity infrared radiation, which is based on the interference of propagation modes in the far field of a multimode fiber. In this report we present new results on the method. The probing light from a coherent light source is injected into the input face of a multimode optical fiber and at the output end of the fiber the modal distribution of the probing light intensity (the speckle image) is registered. When a physical perturbation hits the fiber, the speckle pattern changes.