Southwest Quantum Information and Technology

Practical transmission matrix of a multimode fiber

Presenting Author: Nate Ristoff, Center for Quantum Information and Control (CQuIC), University of New Mexico
Contributing Author(s): F. E. Becerra

Transmission of information through multimode fibers can provide a path to achieving higher capacity than what is currently possible with single mode fibers. However, cross talk between different spatial modes makes information transmission challenging. Therefore a method to reverse intermodal cross talk is required to ensure information transmission with high fidelity. States of light with spatial structure in Laguerre Gaussian (LG) modes are an ideal basis to investigate experimentally the communication capacity of such multimode fibers due to the orthogonality between modes and the infinite size of the basis. The mode structure of LG beams have radial and orbital angular momentum (OAM) degrees of freedom and thus both must be included in a modal decomposition. We investigate a protocol previously used to characterize the output of a few mode fiber and extend it to the study the transmission of light through a fiber with many modes (highly multi-mode fiber) with the goal of increasing information transmission. This protocol allows for a fast determination of the transmission matrix of a multi-mode fiber with a modest number of measurements. In addition, this method does not require a second beam to act as a local oscillator to retrieve inter-modal phase information. This protocol could in principle allow for implementing real time tracking of the transmission matrix of the fiber so that a disturbance in the fiber can be detected and corrected to avoid loss of information.

(Session 5 : Thursday from 5:00pm - 7:00pm)