Optical fiber coupler with attenuator

A fiber optic centrosymmetric reflective attenuation apparatus comprising:

• a concave reflective surface disposed in a centrosymmetric reflective structure;
• first and second optical fiber ends for terminating optical fibers and admitting optical energy to said centrosymmetric reflective structure, said first and second optical fiber ends being disposed for transmitting optical energy from said first fiber end to said second fiber end by reflection upon said concave reflective surface;
• and
• neutral density plate means disposed between said first and second optical fiber ends and said concave reflective surface for attenuating optical energy passing between said first fiber end and said second fiber end wherein said plate means comprises an electronically-controllable variable density neutral density plate fixedly mounted between said first and second optical fiber ends and said reflective surface, said neutral density plate being responsive to application of an electric control signal to vary attenuation of optical energy, and means for applying a control signal to said variable density plate in order to vary attenuation of optical energy directed from said first fiber end to said second fiber end.