METHOD AND APPARATUS FOR ACOUSTIC SENSING USING MULTIPLE OPTICAL PULSES
First Claim
1. A method comprising:
- launching into a medium a first pair of electromagnetic waves comprising a first electromagnetic wave and a second electromagnetic wave; and
sampling a first signal associated with a scattering by the medium of the first pair of electromagnetic waves by extracting phase information including complex signals corresponding to a plurality of fixed locations along the medium.
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Accused Products
Abstract
An improved technique for acoustic sensing involves, in one embodiment, launching into a medium, a plurality of groups of pulse-modulated electromagnetic-waves. The frequency of electromagnetic waves in a pulse within a group differs from the frequency of the electromagnetic waves in another pulse within the group. The energy scattered by the medium is detected and, in one embodiment, may be used to determine a characteristic of the environment of the medium. For example, if the medium is a buried optical fiber into which light pulses have been launched in accordance with the invention, the presence of acoustic waves within the region of the buried fiber can be detected.
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Citations
20 Claims
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1. A method comprising:
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launching into a medium a first pair of electromagnetic waves comprising a first electromagnetic wave and a second electromagnetic wave; and sampling a first signal associated with a scattering by the medium of the first pair of electromagnetic waves by extracting phase information including complex signals corresponding to a plurality of fixed locations along the medium. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system comprising:
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a plurality of sources for launching into a medium a first pair of electromagnetic waves comprising a first electromagnetic wave and a second electromagnetic wave; and an analog-to-digital converter for sampling a first signal associated with a scattering by the medium of the first pair of electromagnetic waves by extracting phase information including complex signals corresponding to a plurality of fixed locations along the medium. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A computer readable medium storing computer program instructions for sampling signals on a medium, wherein a first pair of electromagnetic waves comprising a first electromagnetic wave and a second electromagnetic wave propagates along the medium, the computer program instructions, when executed on a processor, cause the processor to perform operations comprising:
sampling a first signal associated with a scattering by the medium of the first pair of electromagnetic waves by extracting phase information including complex signals corresponding to a plurality of fixed locations along the medium. - View Dependent Claims (17, 18, 19, 20)
Specification