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Multiple Wavelength Input Coupler For Leaky Mode Devices

ID: 2017-065 Multi-wavelength, single angle grating input couplers for internal illumination of leaky mode modulators

ID: 2017-065
Principal Investigator: Daniel Smalley

This invention capitalizes on the idiosyncrasies of leaky mode devices (high index substrate, RGB display applications) to create a grating input coupler that allows light to red, green and blue light to enter the waveguide from the same angle - or even as part of the same 'white' beam - greatly simplifying the process in introducing light into waveguides for leaky mode devices.

Due to the superpositional response of gratings, namely that such gratings can be superimposed upon one area to elicit the same response as each of the contributing grating, it is possible to have multiple wavelength input couplers in the same location. This invention consists in a single grating which will allow for multiple wavelengths to enter at the same angle.

An experiment was conducted where researchers created a waveguide with multiple grating input couplers, each with a different period, and then tested to see at which angle each color of laser (red, green and blue) would couple into the waveguide for each grating.

Because of the binary nature of the masking and etching processes, where an area is either etched to the set depth or is not etched at all, it is possible to superimpose the gratings. By taking the three different grating periods and multiply them together, a new single grating is created that will couple light of all three colors. The red and green grating with equivalent input angle are multiplied, and a red and green and blue grating with equivalent input angles are multiplied, creating a superimposed grating which will accept all base colors.

About the Market:
This technology will be used to make near-eye holographic displays and flat screen holographic displays. The holographic displays global market is expected to reach over $3.5 billion in annual sales by 2020, and $1.82 bllion by 2021 in Americas (driven mainly by growth of commercial and medical industry).

For more information, contact Dave Brown (801-422-4866)

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