Abstract: Disclosed herein is an optical fiber device comprising an optical fiber; the fiber having a first portion with an endface, the endface having a core and a peripheral area around the core, the endface having defined thereon a first region adjacent the core and a second region adjacent the peripheral area; a layer of reflective material located on the endface and confined to the first region, thereby forming a localized reflector thereon.

Abstract: A system for coupling energy between electrical and mechanical waves includes a mechanical waveguide for propagating a mechanical wave having a mechanical wavelength at a given frequency, and an electromechanical energy converter for coupling energy between electrical and mechanical waves attached to a portion of the waveguide and capable of propagating an electrical wave having an electrical wavelength substantially equal to the mechanical wavelength at the given frequency. The portion has a length, measured in units of coupled wavelength, which is selected on the basis of the reciprocal of the coupling strength of the electromechanical converter and a selected amount of wave energy to be coupled. The function is based primarily on desired efficiency and may also be an odd integer multiple of the coupling strength reciprocal, preferably one. Piezoelectric elements are the preferred electromechanical energy conversion elements.