Apparatus and Method for Coherent Acousto-Optic Signal Width Modification
Patent, Filed 3 May 95, patented 13 Oct 98
DEPARTMENT OF THE NAVY WASHINGTON DC
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The invention pertains to a apparatus and method for coherently stretching or compressing signals of interest, i.e., without loss of information. A first, or tapping, Bragg cell has an acoustic signal launched in it which is modulated onto a laser carrier. The signal of interest is launched into a second, or signal, Bragg cell, and is similarly modulated onto the carrier exiting the first Bragg cell. Upon demodulation, the resultant signal, is the convolution of the two acoustic signals in the respective Bragg cells, but whose duration is either stretched or compressed according to the relative velocity between the acoustic signals in the two Bragg cells, and by the magnification of optics between the two cells. If the signal in the first Bragg cell is of such a short duration that it is effectively an impulse, the resultant signal is a coherently stretched or compressed replica of the signal launched into the second Bragg cell, i.e., the signal of interest.
- Lasers and Masers
- Acoustooptic and Optoacoustic Devices