  When cavity photons couple to an optical fiber with a continuum of modes,
they usually leak out within a finite amount of time. However, if the fiber is
about one meter long and linked to a mirror, photons bounce back and forth
within the fiber on a much faster time scale. As a result, {\em dynamical
decoupling} prevents the cavity photons from entering the fiber. In this paper
we use the simultaneous dynamical decoupling of a large number of distant
cavities from the fiber modes of linear optics networks to mediate effective
cavity-cavity interactions in a huge variety of configurations. Coherent cavity
networks with complete connectivity can be created with potential applications
in quantum computing and simulation of the complex interaction Hamiltonians of
biological systems.
