SUBMERSIBLE N-WAVELENGTH INTERROGATION SYSTEM AND METHOD FOR MULTIPLE WAVELENGTH INTERFEROMETERS

摘要

In an in situ interrogation system for multiple wavelength interferometers a fringe spectrum that includes non-quadrature-spaced radiation-intensity samples is analyzed to obtain a high resolution relative phase measurement of the optical path length difference associated with the fringe spectrum. The fringe spectrum can be analyzed to obtain a fringe number and a quadrant as well, which can be combined with the relative phase measurement to obtain a high precision measurement of the absolute optical path length difference. An environmental condition corresponding to the absolute optical path length difference can be measured using the measurement of the absolute optical path length difference including salinity, pressure, density, and refractive index of a medium.

主权项

1. A system for measuring a parameter of interest in situ using a measurement of absolute optical path length difference, the system comprising:
a radiation source adapted to emit electromagnetic radiation; a sample space exposed to an environmental condition and adapted to produce a fringe spectrum from the electromagnetic radiation; a detector capable of detecting the fringe spectrum; and an analysis system comprising a receiver for receiving the fringe spectrum from the detector and a sampler in communication with the receiver for selecting a set of non-quadrature-spaced samples from a plurality of samples; wherein the analysis system derives a measurement of the absolute path length difference and uses the measurement to calculate a parameter of interest.