Circular birefringence is also called optical rotation. An experimental set-up using the photoelastic modulator (PEM) is developed in our lab for measuring small optical rotation in chiral solutions. Sugar solutions at known concentrations are used as standards to test the feasibility of the method and the sensitivity of the instrument. The sensitivity of this current instrument is determined to be 0.001 degrees. Using the same set-up, low-level linear birefringence in optical materials can also be measured at a different harmonic of the PEMs resonant frequency. Examples of monitoring residual linear birefringence for optical elements are given. Recent progress made in our lab is briefly discussed.© (1999) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.