Fiber optic communication system and fiber optic modulator
First Claim
1. A modulator responsive to an electrical signal for changing the polarization state of a light wave transmitted along an optical fiber in accordance with said electrical signal including:
- first and second acoustic transducers for generating first and second acoustic waves, respectively;
means for acoustically coupling said first and second acoustic transducers to said optical fiber for causing the first and second acoustic waves to travel across said optical fiber to compress and decompress the optical fiber;
said first and second acoustic transducers positioned so that said first and second acoustic waves travel across said optical fiber at a nonzero spatial angle that is not an integer multiple of 90 degrees with respect to one another; and
means for exciting said first and second acoustic transducers with said electrical signal, said first and second acoustic transducers positioned and said electrical signal conditioned so that the first and second acoustic waves travel through the fiber with a predetermined nonzero phase relationship, said phase relationship being less than 180 degrees.
1 Assignment
0 Petitions
Accused Products
Abstract
A modulator adapted to be acoustically coupled to an optical fiber for applying acoustic waves across the fiber at a spatial and phase angle with respect to one another to compress and decompress the optical fiber at said spatial angle responsive to an electrical signal whereby to modulate the polarization state of an optical wave travelling past said modulator. An optical communication system in which light waves are transmitted from a transmitting end to a receiving end and whose polarization is modulated by an acoustic modulator responsive to an input signal and the output signal is demodulated to recover the signal.
40 Citations
14 Claims
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1. A modulator responsive to an electrical signal for changing the polarization state of a light wave transmitted along an optical fiber in accordance with said electrical signal including:
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first and second acoustic transducers for generating first and second acoustic waves, respectively; means for acoustically coupling said first and second acoustic transducers to said optical fiber for causing the first and second acoustic waves to travel across said optical fiber to compress and decompress the optical fiber; said first and second acoustic transducers positioned so that said first and second acoustic waves travel across said optical fiber at a nonzero spatial angle that is not an integer multiple of 90 degrees with respect to one another; and means for exciting said first and second acoustic transducers with said electrical signal, said first and second acoustic transducers positioned and said electrical signal conditioned so that the first and second acoustic waves travel through the fiber with a predetermined nonzero phase relationship, said phase relationship being less than 180 degrees. - View Dependent Claims (2, 3, 4, 5)
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6. In an optical communication system for transmitting an input signal from one location to another by modulating with said input signal light waves which travel along an optical fiber:
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an optical fiber extending between said locations; a modulator coupled to said optical fiber having first and second acoustic transducers adapted to be acoustically coupled to said optical fiber to apply first and second acoustic waves across the optical fiber at a spatial angle with respect to one another to each compress and decompress the optical fiber in a region of said optical fiber in response to said input signal, whereby to modulate the polarization of the light waves travelling along said optical fiber past said region, and means for receiving said light wave having modulated polarization and generating an output signal representative of said input signal. - View Dependent Claims (7, 8, 9, 10)
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11. A modulator responsive to an electrical signal for changing the polarization state of a light wave transmitted along an optical fiber in accordance with said electrical signal including:
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first and second acoustic transducers for generating first and second acoustic waves, respectively; means for acoustically coupling said first and second acoustic transducers to said optical fiber for causing the first and second acoustic waves to travel across said optical fiber to compress and decompress the optical fiber, wherein said first and second acoustic transducers are mounted on a substrate having substantially the same acoustical impedance as the optical fiber to couple the first and second acoustic transducers to the optical fiber; said first and second acoustic transducers positioned so that said first and second acoustic waves travel across said optical fiber at a spatial angle with respect to one another; and means for exciting said first and second acoustic transducers with said electrical signal, said first and second acoustic transducers positioned and said electrical signal conditioned so that the first and second acoustic waves travel through the fiber with a predetermined phase relationship. - View Dependent Claims (12)
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13. A modulator responsive to an electrical signal changing the polarization state of a light wave transmitted along an optical fiber in accordance with said electrical signal including:
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first and second acoustic transducers for generating first and second acoustic waves, respectively; means for acoustically coupling said first and second acoustic transducers to said optical fiber for causing the first and second acoustic waves to travel across said optical fiber to compress and decompress the optical fiber; said first and second acoustic transducers positioned so that said first and second acoustic waves travel across said optical fiber at a spatial angle of substantially 45 degrees with respect to one another; and means for exciting said first and second acoustic transducers with said electrical signal, said first and second acoustic transducers positioned and said electrical signal conditioned so that the first and second acoustic waves travel through the fiber with a predetermined phase relationship of substantially 90 degrees. - View Dependent Claims (14)
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Specification