The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 17, 2018
Filed:
Mar. 07, 2016
Photonics Electronics Technology Research Association, Tokyo, JP;
Masatoshi Tokushima, Tokyo, JP;
Jun Ushida, Tokyo, JP;
Abstract
A grating structure for a grating coupler is provided which has a high efficiency resulting from the operating principle, is easily manufactured, and simultaneously has little reflection loss. This grating structure is provided with a core layer having periodic recesses and protrusions formed on the upper surface, a first upper cladding layer in contact with the upper surface of the core layer, a second upper cladding layer in contact with the upper surface of the first upper cladding layer, and a first lower cladding layer in contact with the lower surface of the core layer. The recessed portions of said recesses and protrusions are filled with the same material as the first upper cladding layer. The refractive index of the material forming the core layer is greater than the refractive index of the materials forming the first upper cladding layer, the second upper cladding layer and the first lower cladding layer. The refractive index of the material of the first upper cladding layer is greater than the refractive index of the material of the second upper cladding layer. The thickness from the upper surface of the protruding portions of the recesses and protrusions to the upper surface of the first upper cladding layer is within the range obtained by subtracting ½ of the depth of the recesses and protrusions from ((2m−1)/4±⅛) times (mbeing a positive integer) the wavelength, in the material forming the first upper cladding layer, of light inputted and outputted by the grating coupler.