Patent ID: 7483598
Filing Date: 2009-01-27
Classification: G01J,G01N

Abstract:
1. An apparatus for measuring one or more optical properties of a test medium, comprising: a passive optical waveguide loop that provides a continuous path for a light signal launched into the loop to travel around the loop repeatedly, the loop adapted to accept a test medium such that the light signal traveling around the loop interacts with the test medium each time the light signal travels around the loop; an intensity-modulated light source for illuminating the loop with a light signal at an intensity modulation envelope reference phase; a detector for detecting a phase of the intensity modulation envelope of said light signal along the loop; and an analyzer for comparing the detected phase of the intensity modulation envelope of the light signal with the reference phase of the intensity modulation envelope of the light signal; wherein a result of the comparison is indicative of one or more optical properties of the test medium.