Single-mode excitation of step-index multimode fibers with light sources with short temporal coherence lengths is demonstrated. Multimode fiber designs with reduced microbending-induced mode coupling are described that allow the propagation of the fundamental mode over long lengths with negligible mode coupling even in the presence of tight fiber bends. At a wavelength of 1.56µm a fiber with a core diameter of 45µm can preserve the fundamental mode for a propagation length of ~20m . Such fibers allow coiling with a coil diameter as small as 7cm.
© 1998 Optical Society of America
Martin E. Fermann, "Single-mode excitation of multimode fibers with ultrashort pulses," Opt. Lett. 23, 52-54 (1998)