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AssigneeThe Secretary of State for Defence in Her Britannic Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
InventorsHerbert A. French, Philip Sutton
Estimating the term…
An interference device for discriminating between radiation sources of differing coherence length comprises means to divide received radiation from a source into two components. A path difference, defining a coherence length cut-off, is introduced into the path of one component and the components are brought together for interference. The recombined light passes through a reticle with alternate opaque and tranparent bars and an optical band-pass filter to a detector. Interference fringes present in the plane of the reticle are swept across the reticle by the action of the collection optical system of the device which includes a scanning rotating mirror. Two similar devices can be arranged for band-pass coherence length filtering and when used in conjunction with a light soruce whose coherence is modulated the device can be used for signalling.
A coherence length filter device for detection of coherent radiation from a source having a coherence length in a given range including:
A coherence length filter arranged for detecting coherent radiation having a coherence length within a given range including first and second interference devices, each of said device comprising means for receiving coherent radiation emitted by the source, means for dividing received radiation into two components, means for recombining the components with a path difference therebetween, means for selectively modulating radiation from interference fringes produced by the recombination, and radiation detection means arranged for selective response to modulated radiation, the arrangement being such that the path differences of the first and second interference devices are different and the detection means from the first and second interference devices are connected to a comparator means for comparing the responses from the said two detection means.
A coherence length filter arranged for detecting radiation having a coherence length within a given range comprising means for dividing received radiation into two components, means for recombining the components with a path difference there-between, a first means for selectively modulating radiation from first interference fringes produced by the recombination, means for partially delaying and recombining radiation from said first interference fringes to form a second set of interference fringes, a second means for selectively modulating the second set of interference fringes and radiation detection means for selectively detecting and distinguishing the modulations introduced by the said first and second modulation means.
A communications transmitter/receiver including:
Dependencies are inferred from the claim text.