Abstract

Transverse modes in optical fibers have gained increasing interest in the recent years. For the measurement of the modal amplitude and modal phase in a fiber, several techniques exist examining the spatial distribution of the light exiting the fiber end facet [1,2]. However, such techniques are not suitable for inline monitoring of the modal content in an all-fiber application, like lab-on-a-tip sensing applications, where the distal end of the fiber is not accessible. Here, we present an inline-measurement technique for modal phase differences and experimentally demonstrate the direct measurement of all-optically induced changes of the modal phase difference by intermodal cross-phase modulation (intermodal XPM) [3].

© 2019 IEEE