Patent
1985-02-08
1988-04-05
Lee, John
350 9615, 350358, 350371, G02F 202
Patent
active
047354844
ABSTRACT:
A fiber optic frequency shifter comprises an optical fiber having an acoustic conducting medium for propagation of an acoustic signal. The acoustic medium is preferably shaped as a rod, and the acoustic signal propagates longitudinally down the rod. The optical fiber is wound around the rod with plural turns such that the axis of the fiber is at an angle relative to the wave fronts of the acoustic signal. As the acoustic signal propagates through the rod, it causes stress on the portions of the fiber in contact with the rod. The stress on the fiber caused by the acoustic wave causes optical energy to be transferred between two propagation mdes of the fiber. This transferred energy is shifted in frequency by the frequency of the acoustic signal. By tightly winding the turns of the fiber, high frequency shifts can be obtained. The invention is also advantageous in that it provides a large amount of acoustic contact between the acoustic wave fronts and the fiber over a relatively short acoustic propagation distance. Thus, the device is quite compact.
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Board of Trustees of the Leland Stanford Junior University
Lee John
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