Patent ID: 11940386
Assignee: THE UNIVERSITY OF BRITISH COLUMBIA
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 27:
28. Apparatus for monitoring a sample for at least one analyte, the apparatus comprising:
an optical waveguide comprising a sensing portion and a phase shift portion wherein the sensing portion passes through a volume for receiving the sample;
a fixed wavelength light source coupled to deliver fixed wavelength light into the waveguide;
a phase shift modulator operative to periodically modulate a phase shift of the light effected by the phase shift portion of the optical waveguide;
at least one light detector operable to monitor an intensity of the light relative to the phase shift of the light effected by the phase shift portion of the waveguide; and
an optical switch upstream from the light detector and a lock-in control system configured to switch the optical switch according to a signal Vch1(t) and the apparatus comprises a mixer connected to receive an output of the light detector and to mix a signal Vch2(t) with the output of the light detector.