Stationary inflection points in optical waveguides: Accessible frozen light

Stationary Inflection Points (SIPs) around a frequency ω₀ are of the form ω-ω₀ ∝ k^m for any positive odd integer. We show theoretically that SIPs of order m can be created in optical waveguides such as optical fiber gratings or periodic nanobeam waveguides by coupling between m modes. Remarkably, we find that at the SIP frequency significant incident energy can be coupled into the waveguide even though the group velocity of the associated mode is zero. Here we demonstrate this frozen light for cubic (k³) and quintic (k⁵) SIPs and relate it to the existence of evanescent modes at the interface and demonstrate it.