Reflection of whispering gallery modes propagating on a surface of an optical fiber from its cleave.

We experimentally and numerically study the dynamics of whispering gallery modes slowly propagating within the cladding of an optical fiber near its end facet. We demonstrated that modes reflect from the fiber cleave. The reflection coefficient appears to reach 70% for the sample under study. Use of a facet provides a simple method to confine the axial propagation of the modes.