Global and local speckle variation in tensioned multimode fiber

摘要

We experimentally demonstrate strain-induced speckle variation. When we take the whole speckle into consideration, the correlation function under different strain decreases dramatically at the beginning, and then it saturates as strain increasing. This tendency has nothing to do with the input wavelength and the length of multimode fiber (MMF), thus the operating cost will be largely reduced if multimode speckle is applied in sensor or imaging systems. The correlation coefficient of speckle patterns under different wavelengths is hardly affected by strain. The length of MMF can tune the decreasing trend when the strain is not large. Via space division of speckle pattern, the detail information can be obtained by calculating the correlation coefficient or intensity of every tiny part. To the best of our knowledge, the detail information of speckle under different strain is performed in experiment firstly. The research results can be utilized in future biomedical imaging, compressed sensing and new concept all-optical devices.