US 11,852,832 B1
Waveguide with four gradient coating
Yiren Xia, Milton Keynes (GB); and Timothy Smeeton, Milton Keynes (GB)
Assigned to ENVISICS LTD, Milton Keynes (GB)
Filed by Envisics Ltd, Milton Keynes (GB)
Filed on Apr. 28, 2023, as Appl. No. 18/141,311.
Claims priority of application No. 2214069 (GB), filed on Sep. 27, 2022.
Int. Cl. G02B 27/01 (2006.01); G02B 27/00 (2006.01)
CPC G02B 27/0172 (2013.01) [G02B 27/0081 (2013.01); G02B 27/0103 (2013.01); G02B 2027/0109 (2013.01)] 25 Claims
OG exemplary drawing
 
1. A waveguide comprising a pair of parallel surfaces arranged to provide waveguiding therebetween, wherein a first surface of the pair of parallel surfaces comprises a plurality of layers of a first dielectric and a plurality of layers of second dielectric arranged in an alternating configuration, wherein each layer of the first and second dielectric has a first end and a second end,
wherein a percentage change in the thickness of each layer from the first end to the second end of that layer has one of a plurality of discrete allowable values; wherein the total number of layers of the first and second dielectric is greater than the total number of discrete allowable values; wherein a difference in refractive index between the first dielectric and second dielectric is greater than 0.4; and
wherein the first dielectric comprises a first oxide, fluoride, sulfide or nitrate of a first transition metal or semiconductor and the second dielectric comprises a second oxide, fluoride, sulfide or nitrate of a second transition metal or semiconductor.