摘要 |
A fiber-optic laser Doppler interferometer includes a MM interferometric coupler configured with a double-clad MM fiber having a core, inner cladding and outer cladding. The core of the double clad MM fiber delivers a single mode radiation of a laser source towards a vibrating scattering surface which, in response thereto, scatters a beam launched back into the delivery fiber so that the inner cladding supports MM radiation. As a result of interferometric beating of the reference and scattered beams against each other in the MM coupler, the latter continuously outputs an amplitude-modulated signal which is not substantially affected by a speckle fading effect.
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