An apparatus, system, and method for enabling multi-frequency communication over a telephone network having a billingtax tone are disclosed. A light emitting element is provided on an upper surface of a first under-cladding layer, and a second under-cladding layer is provided on the upper surface of the first under-cladding layer, covering the light emitting element. A first reactant is fed from the first reactant source in the form of repeated alternating pulses to a reaction chamber via a first conduit.