US 12,468,034 B2
Phase difference detection system and a method for detecting a phase difference
YanLu Li, Kessel-Lo (BE); and Roeland Baets, Deinze (BE)
Assigned to Imec vzw, Leuven (BE); and Universiteit Gent, Ghent (BE)
Appl. No. 17/604,950
Filed by Imec vzw, Leuven (BE); and Universiteit Gent, Ghent (BE)
PCT Filed May 4, 2020, PCT No. PCT/EP2020/062265
§ 371(c)(1), (2) Date Oct. 19, 2021,
PCT Pub. No. WO2020/225187, PCT Pub. Date Nov. 12, 2020.
Claims priority of application No. 19173535 (EP), filed on May 9, 2019.
Prior Publication US 2022/0214456 A1, Jul. 7, 2022
Int. Cl. G01S 17/58 (2006.01); G01B 5/02 (2006.01); G01S 7/481 (2006.01); G01S 7/4915 (2020.01)
CPC G01S 17/58 (2013.01) [G01S 7/4812 (2013.01); G01S 7/4818 (2013.01); G01S 7/4915 (2013.01); G01B 5/02 (2013.01)] 20 Claims
OG exemplary drawing
 
11. A method for detecting a phase difference between two laser beams due to reflection at a target location, the method comprising:
guiding a laser beam within a planar waveguide having a normal direction;
splitting the laser beam using a grating coupler into a reference beam and a measurement beam, wherein the measurement beam is directed towards the target location and the reference beam is directed away from the target location, the reference beam and the measurement beam each being inclined with respect to the normal direction;
detecting a fringe pattern generated by the reference beam and an incoming beam, the incoming beam being the result of the measurement beam having been reflected at the target location and having passed through the grating coupler; and
deriving a phase difference between the reference beam and the incoming beam based on the fringe pattern.