A new sensor is presented for detecting surface acoustic waves. The sensor constructed, using single mode fiber components, is small and rugged and has better sensitivity (.0003 Å) than has been reported for other SAW sensors. Optical reflection changes encountered while scanning surfaces can be divided out, making the probe applicable to rough samples of practical interest. Normal surface displacements near a defect (100 μm deep crack) have been measured in both long and short wavelength acoustic regimes.