The determination of differential phase introduced bydisplacement with interferometric technique is widelyemployed, for example, in the production control [1] orlever deflection of atomic force microscope [2] where thenon-contact and high resolution with nanometric scale isrequired. These measurements also require many aspectsof design, instrumentation and analysis techniques. Amongvarious interferometric interrogation methods for measuring the displacement in real time, quadrature detectionassociates with homodyne [3] or heterodyne [4] interferometry is attractive. This is because the quadrature detectionpermits wide dynamic range on phase measurement dueto high resolution of fringe sub-division and the capabilityof direct accessing the instantaneous differential phase.Moreover, the in phase signal and its quadrature component can be treated as the components of a vector in complex coordinate, the direction of rotation of this vector andthe phase represented by the rotation angle can be determined, which resolves the 2p phase ambiguity in traditionalinterferometric technique. However, in typical quadraturedetection technique, the separation of signal in equalamplitudes is required and an exact p/2 phase shift of localoscillator is required to extract the in phase and quadraturecomponents, these two requirements are difficult to achievesince the non-ideal response of electronic device involved.Thereby, a more complicate differential quadrature phasedetection scheme for eliminating the non-ideal responsewas proposed by Vergamota et al.