Multichannel Wdm Vibrometry At 1550 Nm

We present a multichannel laser-fiber vibrometer concept, realization and obtained results. The vibrometer is based on the WDM (Wavelength Division Multiplexing) telecommunication technique and operates at the 1550 nm region. Four independent fiber-coupled laser diodes form a system of sources for multipoint vibration measurement according to the rule "one wavelength-one point". Such a solution minimizes crosstalk between channels and allows to arrange measuring points freely. Our system measures vibrations at four points simultaneously. It allows phase-relation measurements between vibrating points. Additionally, it is an all fiber design thus it gives the possibility to measure vibrations in hard-to-reach places.