Device for emission of arbitrary optical beam profiles from a chip to free space

An optical coupler device, comprising:

• a substrate having a substantially planar upper surface;
• a grating structure on the upper surface of the substrate, the grating structure comprising an array of zig-zag grating lines, wherein the grating structure is defined by an x-y-z coordinate system having an x-axis and z-axis that define an x-z plane, and a y-axis that is substantially perpendicular to the x-z plane, wherein the array of zig-zag grating lines are along the x-z plane;
• and
• an input port in optical communication with the grating structure, the input port configured to direct an input light beam into the grating structure substantially along the z-axis;
• wherein each of the zig-zag grating lines is positioned substantially perpendicular to a propagation direction of the input light beam;
• wherein the grating structure is configured to diffract the input light beam out of the grating structure substantially along the y-axis and into free space.

A method of fabricating an optical coupler device, the method comprising:

• providing a substrate layer having an upper surface, the substrate layer including a first material having a first refractive index;
• depositing a guiding layer on the upper surface of the substrate layer, the guiding layer including a second material having a second refractive index that is higher than the first refractive index;
• and
• forming a grating structure in at least a portion of the guiding layer, the grating structure comprising an array of grating lines, wherein each of the grating lines has a periodic structure along a length thereof with a substantially uniform periodic amplitude wherein the grating structure is defined by an x-y-z coordinate system having an x-axis and z-axis that define an x-z plane, and a y-axis that is substantially perpendicular to the x-z plane, wherein the array of grating lines extend along the x-z plane;
• wherein the grating structure is configured to diffract an input light beam, propagating substantially along the z-axis, out of the grating structure substantially along the y-axis and into free space.