Eggleton's research links fundamental to applied science and spans physics and engineering. He has made pioneering contributions to nonlinear optics and all-optical signal processing with recent breakthrough achievements in the nonlinear optics of periodic media, slow-light in photonic crystals and ultrafast planar waveguide nonlinear optics. His research into new classes of nonlinear waveguides has created a new paradigm for photonic chip based ultrafast optical signal processing and his group holds various world records.

Eggleton's breakthroughs in the nonlinear optics of chalcogenide glasses have led to his demonstrations of new ultrafast optical devices for telecommunications applications, record low-threshold supercontinuum generation sources and on-chip parametric sources. His group reported the first demonstration of on-chip stimulated Brillouin scattering, and holds the record for on-chip SBS gain. His fundamental breakthroughs include the first demonstrations of gap soliton formation in periodic media and of slow-light-enhanced nonlinear optics in photonic crystals.