The gravitational phase shift test of general relativity
  The aim of this paper is to study the extra phase shift that general relativity (GR) predicts for a radial light ray propagating in the vicinity of a static spherical symmetric body. It appears that the gravitational phase shift test yields a better sensitivity than the gravitational frequency shift or the excess time delay of the photons. An experiment is proposed for this new test of GR pertaining exclusively to the wave aspect of light. 
Jean Paul Mbelek