  An incoming gravity wave being a stress wave is a surface with intrinsic
curvature. When a light beam is parallel transported on this non-Euclidian
surface it acquires an excess phase which accumulates with each curcuit. We
calculate the separate contributions to excess phase from the wave geometry as
well as the dynamic response of mirrors in a Michelson interferometer. Using
these results and a combination of analogue and digital signal processing
techniques we show how a compact interferometer can be made sensitive to
gravity waves of amplitude density $10^{-23}/\sqrt{Hz}$ within a frequency
range $10^{-4}Hz$ to $10^4Hz$. As an example we describe a 10cm Michelson
interferometer designed to measure gravity waves from sources as far as the
Virgo cluster.
