Optical modulators
AssigneeNorthern Telecom Limited
InventorKevin S. Gordon
Life of this patent
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Abstract
An optical modulator has two closely spaced optical fibre end surfaces, the optical path length between which can be altered in response to an applied modulating signal. Light is partially reflected from the two surfaces, the two beams interfering according to their phase difference. Alternatively the modulator may be operated in a transmissive mode. To obtain modulation either the refractive index of material between the fibre end surfaces is altered or one of the fibres is longitudinally vibrated. A method of operating a modulator in a wavelength selective mode is also described.
Claims12
An optical modulator suitable for a fibre optic telecommunications system, said modulator comprising a pair of contiguous fibres, an end surface of one fibre facing, spaced from, and parallel to an end surface of the other fibre, whereby light directed along one fibre is partly reflected from the spaced fibre ends and is partly transmitted at said spaced fibre ends into the fibre, and means for altering the optical path length between the fibre end surfaces said alteration of optical path occurring in accordance with an applied modulating signal whereby to vary the intensity ratio of the partly reflected and the partly transmitted light.
Dependencies are inferred from the claim text.