| 摘要 |
A direct detection method and apparatus for a fiber optic acoustic sensor array systems using an in-line Michelson sensor TDM array and an interferometric section having two acousto-optic modulators that produce optical pulses that are frequency shifted with respect to each other. Direct detection is accomplished according to the equation: I(t)=A+B cos [phi<SUB>1</SUB>-phi<SUB>2</SUB> +2 pi (f<SUB>1</SUB>-f<SUB>2</SUB>) t], with the phase shift difference phi<SUB>1</SUB>-phi<SUB>2 </SUB>between two paths containing the acoustic phase information and the frequency f<SUB>1</SUB>-f<SUB>2 </SUB>being the difference between the RF frequencies for the two acousto-optic modulators.
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