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US 5,513,284 AGranted
Method and a device for correlating two or more optical pulse signals
AssigneeLycom A/S
InventorsJan Th.o slashed.gersen, Jannik Mark
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AssigneeLycom A/S
InventorsJan Th.o slashed.gersen, Jannik Mark
Estimating the term…
The object of the invention is to provide a method which makes it possible to determine the correlation between two optical signals, which makes it possible to correlate two optical signals, without using a crystal element which is associated with a plurality of drawbacks, because the components are quite expensive. It has been found possible to replace a frequency doubling crystal by an active, optical wave guide, e.g. in the form of an active, optical fiber, said wave guide transmitting fluorescence which is intensity-related to the arrived signal. When this fluorescence is detected in spectral bands, e.g. in the blue region of the visible light, an image of the strength of the arriving signal may be formed. Current distance delaying of the two correlated signals makes it possible to produce an image of the correlation between the signals.
A method of correlating two or more optical pulse signals by passing one of them through respective optical paths of which at least one has a variable delay element so that the pulse signals can be delayed temporally with respect to each other, said correlation between the pulse signals being determined in response to the interaction of the signals with a photoreactive element, characterized by passing the pulse signals to an active, optical wave guide doped with optical, active ions, detecting fluorescence originating from the combination of the optical signals with the active ions, and determining the correlation between the pulse signals in response to the detected fluorescence.
A device for correlating two or more optical pulse signals, comprising respective optical paths for the pulse signals, at least one of said paths having a variable delay element so that the pulse signals can be delayed temporally with respect to each other, as well as a photoreactive element which, by interaction with the signals, emits a signal by means of which the correlation of the pulse signals can be determined, characterized in that the device comprises an active, optical wave guide as the photoreactive element to which the pulse signals are applied, said wave guide being doped with optical, active ions, a detector arranged in connection with the wave guide to detect fluorescence originating from the wave guide as a consequence of the combination of the optical signals with the active ions, and a unit for computing the correlation between the pulse signals in response to the detected fluorescence.
Dependencies are inferred from the claim text.