US 11,923,898 B2
Calculation of distributed birefringence and polarization mode dispersion from waveguide scatter with full polarization state optical frequency domain reflectometry
Stephen T. Kreger, Blacksburg, VA (US); Emily E. H. Templeton, Schenectady, NY (US); Daniel Kominsky, Christiansburg, VA (US); and Brian Templeton, Schenectady, NY (US)
Assigned to LUNA INNOVATIONS INCORPORATED, Roanoke, VA (US)
Appl. No. 17/603,483
Filed by LUNA INNOVATIONS INCORPORATED, Roanoke, VA (US)
PCT Filed Apr. 15, 2020, PCT No. PCT/US2020/028204
§ 371(c)(1), (2) Date Oct. 13, 2021,
PCT Pub. No. WO2020/214637, PCT Pub. Date Oct. 22, 2020.
Claims priority of provisional application 62/833,985, filed on Apr. 15, 2019.
Prior Publication US 2022/0182141 A1, Jun. 9, 2022
Int. Cl. H04B 10/07 (2013.01); H04B 10/071 (2013.01); H04B 10/079 (2013.01)
CPC H04B 10/07951 (2013.01) [H04B 10/071 (2013.01)] 30 Claims
OG exemplary drawing
 
1. A method for determining birefringence of a waveguide segment at a particular location along the waveguide, where the waveguide has a first index of refraction for a first polarization state and a second, different index of refraction for a second polarization state that is substantially orthogonal to the first polarization state, the method comprising:
coupling light with a first polarization state into the waveguide;
detecting, at a polarization diverse receiver, first polarization state back scatter reflections associated with the waveguide segment corresponding to a first set of polarization state values;
generating first polarization state back scatter data associated with the first polarization state back scatter reflections;
coupling light with a second polarization state into the waveguide that is substantially orthogonal to the light with the first polarization state;
detecting, at a polarization diverse receiver, second polarization state back scatter reflections associated with the waveguide segment corresponding to a second set of polarization state values different from the first set of polarization state values;
generating second polarization state back scatter data associated with the second polarization state back scatter reflections;
determining a spectral response based on the first polarization state back scatter data and the second polarization state back scatter data;
computing a correlation based on the spectral response;
determining the birefringence of the waveguide segment at the particular location along the waveguide based on the correlation; and
using the determined birefringence to characterize the waveguide segment.