Fiber optics DSPI for in situ diagnostics

A simple and accurate digital speckle pattern interferometer (DSPI), that uses a single mode bidimensional fiber coupler as beam splitter is described. As a result, the in-plane or out-of-plane displacement components can be measured in real-time and also in an outdoor environment. Preliminary tests have been carried out using a HeNe laser. Further tests are now in progress; the flexibility and compactness of such a system lends itself to use for non-destructive testing of structures, difficult to analyze with a conventional optical arrangement.