Multiplexed fiber optic sensor
First Claim
1. A low power all fiber optic hydrophone array, comprising:
- an optical signal source;
a transmitting optical fiber for guiding signals output from the optical signal source;
a plurality of sensing interferometers coupled to the transmit optical fiber, each sensing interferometer having a short arm and a long arm;
a receive fiber coupled to each of the sensing interferometers; and
means for measuring differential changes in the optical path of each sensing interferometer, including;
means for superimposing signals output from each sensing interferometer;
a detector for converting optical signals in the receive fiber into electrical signalsa transmit interferometer formed in the transmit fiber between the optical source and the sensing interferometer; and
means formed in the transmit interferometer for modulating the optical waves.
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Accused Products
Abstract
An all fiber optic hydrophone or sensor array has significant size, cost, reliability, and operational advantages over other hydrophone arrays. The array comprises a distributed network of appropriately coiled optical fiber encased in commercially available marine cable. The terminal end of the sensor array preferably contains a modulated miniature solid-state laser diode and photodetector matrix which mate to power and multiplexing electronics. The distributed sensor assembly itself is entirely passive. The hydrophone array comprises an optical signal source and at least one transmitting optical fiber for guiding signals output from the optical signal source. The array further includes a plurality of sensing interferometers coupled to the transmit optical fiber and means for measuring differential changes in the optical path of each sensing interfereometer. The hydrophone array comprises means for superimposing signals output from each sensing interferometer, and a detector for converting optical signals in the receive fiber into electrical signals. The signal processing system in the array includes a compensating interferometer having optical phase modulating means formed in one arm thereof.
59 Citations
6 Claims
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1. A low power all fiber optic hydrophone array, comprising:
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an optical signal source; a transmitting optical fiber for guiding signals output from the optical signal source; a plurality of sensing interferometers coupled to the transmit optical fiber, each sensing interferometer having a short arm and a long arm; a receive fiber coupled to each of the sensing interferometers; and means for measuring differential changes in the optical path of each sensing interferometer, including; means for superimposing signals output from each sensing interferometer; a detector for converting optical signals in the receive fiber into electrical signals a transmit interferometer formed in the transmit fiber between the optical source and the sensing interferometer; and
means formed in the transmit interferometer for modulating the optical waves. - View Dependent Claims (2, 3)
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4. A method for forming a low power all fiber optic hydrophone array, comprising the steps of:
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providing an optical signal source; guiding signals output from the optical signal source along a transmit optical fiber; coupling a plurality of sensing interferometers to the transmit optical fiber; forming each sensing interferometer to have a short arm and a long arm; coupling a receive fiber to each of the sensing interferometers; and measuring differential changes in the optical path of each sensing interferometer by the steps of; superimposing signals output from each sensing interferometer; converting optical signals in the receive fiber into electrical signals; forming a transmit interferometer in the transmit fiber between the optical source and the sensing interferometers; and forming optical wave modulating means in the transmit interferometer. - View Dependent Claims (5, 6)
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Specification