We experimentally generate and characterize eigenstates of the Wigner-Smith time-delay matrix, called principal modes, in a multimode fiber with strong mode coupling. The unique spectral and temporal properties of principal modes enable global control of temporal dynamics of optical pulses transmitted through the fiber, despite random mode mixing. Our analysis reveals that well-defined delay times of the eigenstates are formed by multipath interference, which can be effectively manipulated by spatial degrees of freedom of input wave fronts. This study is essential to controlling dynamics of wave scattering, paving the way for coherent control of pulse propagation through complex media.
Bibliographical noteFunding Information:
We acknowledge Chia Wei Hsu, Joel Carpenter, and Nicolas Fontaine for interesting discussions. This work is supported partly by the U.S. National Science Foundation under the Grants No. ECCS-1509361 and No. DMR-1205307. P.A. and S.R. acknowledge support by the Austrian Science Fund (FWF) through projects SFB NextLite (F49-P10) and project GePartWave (I1142).
© 2016 American Physical Society.