We demonstrate an intermodal Čerenkov radiation effect in a higher-order-mode (HOM) fiber with a mode crossing (i.e., two guided modes having the same propagation constant at the same wavelength). A frequency-shifted soliton in the vicinity of the mode-crossing wavelength emits a phase-matched dispersive wave in a different propagation mode. We develop a theoretical explanation for this nonlinear optical effect and demonstrate that the mode crossing in HOM fibers can be utilized to achieve simultaneous wavelength and mode conversion; the strength of this intermodal nonlinear interaction can be tuned by controlled fiber bending.
© 2012 Optical Society of America
Original Manuscript: August 10, 2012
Manuscript Accepted: September 11, 2012
Published: October 19, 2012
Ji Cheng, Martin E. V. Pedersen, Kriti Charan, Ke Wang, Chris Xu, Lars Grüner-Nielsen, and Dan Jakobsen, "Intermodal Čerenkov radiation in a higher-order-mode fiber," Opt. Lett. 37, 4410-4412 (2012)