Macrobend loss reduction of a fiber interferometer using graded-index multimode fiber

An optical fiber interferometer can be used to measure the pressure change between adjacent locations along a capillary tube without disturbing the fluid flow within the tube. The current work demonstrates that a novel configuration of a concatenated SM-MM-SM fiber structure, named SMS, can be used to minimize the macrobend loss of an interferometer that senses pressure changes in small capillary tubes.