Birefringent multi-peak optical reference element and birefringent sensor system
AssigneeWeatherford Technology Holdings, LLC
InventorDomino Taverner
Life of this patent
Estimating the term…
Abstract
Certain aspects of the present disclosure generally relate to an optical reference element having a wavelength spectrum comprising a plurality of wavelength functions having wavelength peaks spaced over a range of wavelengths, wherein adjacent wavelength functions are due to two orthogonal birefringence axes in the optical reference element. Aspects of the present disclosure may eliminate the drift issues associated with residual polarization and polarization dependent loss (PDL) with respect to grating-based sensor and reference element measurements.
Claims22
A reference optical sensor comprising a core with a modulated refractive index, wherein:
- in response to light introduced into the reference optical sensor, the modulated refractive index is configured to produce a wavelength spectrum comprising multiple pairs of wavelength functions having wavelength peaks spaced over a range of wavelengths;
- adjacent wavelength functions in each pair are due to two orthogonal birefringence axes resulting from anisotropic stress on the core of the reference optical sensor, wherein the anisotropic stress on the core is configured to produce distinct wavelength peaks attributed to each of the two orthogonal birefringence axes;
- the wavelength peaks from the multiple pairs of wavelength functions are uniformly spaced over at least a portion of the range of wavelengths at a particular temperature and pressure;
- and
- the refractive index of the core has a periodic modulation corresponding to the uniform spacing of the wavelength peaks from the multiple pairs of wavelength functions.
A reference optical sensor, wherein:
- in response to light introduced into one core of the reference optical sensor, a modulated refractive index of the core is configured to produce a wavelength spectrum comprising multiple pairs of wavelength functions having wavelength peaks spaced over a range of wavelengths;
- adjacent wavelength functions in each pair are due to two orthogonal birefringence axes in the reference optical sensor;
- the wavelength peaks from the multiple pairs of wavelength functions are uniformly spaced over at least a portion of the range of wavelengths at a particular temperature and pressure;
- and
- the refractive index of the core has a periodic modulation corresponding to the uniform spacing of the wavelength peaks from the multiple pairs of wavelength functions.
Dependencies are inferred from the claim text.