Dense silicon-nitride PIC design and manufacturing on transparent substrate for a retinal projector evaluation
26 January 2022 • 10:00 AM - 10:20 AM PST | Room 305 (Level 3 South)
We are developing a non-conventional retinal projector for augmented reality (AR) applications. In our concept, light at λ = 532 nm is guided in silicon-nitride (SiN) photonic integrated circuits (PICs) embedded in the lens of a pair of glasses. We use holographic elements to transmit the emissive points towards the user’s retina without using lenses. Pixels are formed in the eye using the self-focusing effect and the eye lens. The transparency of the device is an absolute requirement for our application. In this work, we present the fabrication and the characterization of our latest SiN PICs on transparent substrate. The device was fabricated by transferring the SiN PICs from a silicon to a glass substrate. We characterized the PICs and the free-space optical transmission properties of our device using in-house goniometers and a Modulation Transfer Function (MTF) setup. We found a 76% transparency at our wavelength and no image alteration. However, we measured significant waveguide propagation losses; solutions are discussed to tackle this problem. Our glass-substrate device is a major step towards a future prototype for our AR retinal projector.
Univ. Grenoble Alpes, CEA-LETI (France), Institut de Microélectronique Électromagnétisme et Photonique et le Lab d'hyperfrequences et Caracte (France)
Kyllian Millard is a second year PhD student in the field of integrated photonics in the visible spectrum applied to augmented reality. After graduating in September 2020 as a physics engineer from the INSA Toulouse engineering school in France, he started his PhD at the CEA-Leti in Grenoble, France.