A system for forming an optical trap comprising two or more photonic crystal fibers and at least one source of radiation for inputting radiation to the photonic crystal fibers, the fibers being operable to provide counter-propagating outputs for forming the optical trap. The regulated voltage can be varied to provide dimming of the fluorescent lamp. The transfer triggering condition includes presence of a second client device or system within a predefined proximity of the first client device or system, and the predefined proximity is a predefined proximity for near field communication. The digital signal can then be processed in a continuous-time signal processor.