Interferometric noise reduction in fiber-optic links by superposition of high frequency modulation

The reduction of interferometric noise by superposition of high frequency modulation is analyzed. It is shown that the nature of this reduction is due to a redistribution of noise energy from baseband to higher frequencies where it can be discarded by low-pass filtering. Detailed analysis revealed the dependence of the noise reduction factor on the product f/sub 0 tau /, and the modulation index of the high frequency superimposed modulation. The proper choice of parameters can lead to complete elimination of the converted phase noise from the system.<
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