Patent ID: 6767515
Filing Date: 2004-07-27
Classification: G01N

Abstract:
A tunable laser cavity sensor chip comprising:(a) a reference laser and a sensor laser, each comprising a waveguide having a gain section, opposing mirrors including a partially transmissive mirror, and a coherent light beam output section, at least one of the waveguides having a phase control section, the coherent light beam output sections being joined to enable coherent light outputs of the reference and sensor lasers to interfere; (b) a sensor region physically separate from said phase control section formed through and exposing the evanescent optical field of the sensor laser, for receiving a sample to be diagnosed; and (c) a heterodyne detector at the juncture of the reference and sensor coherent light output sections for detecting a change in the frequency of the coherent light output from the sensor laser resulting from a change in the index of refraction of fluid in the sensorcavity.