A single-beam probe method for roll angle measurement

A simple common path polarization interferometer was proposed to measure a roll angle change by using a Zn-indiffused lithium niobate waveguide phase modulator for optical homodyne metrology. A phase retardation plate was used for a roll angle sensor. The phase delay between two orthogonal polarizations of a probe light is dependent on the angular displacements of the roll sensor. Experimental results have shown that the roll angle measurement resolution is 0.005μ in a ±0.5μ range.