Towards RGB Combiner for AR/VR applications on AlOx

Abstract: Aluminum oxide (AlOx) offers low optical loss and high transparency in the visible spectrum, making it a promising material for integrated photonics in display technologies such as augmented/virtual reality (AR/VR) and glassless 3D displays. This paper explores the development of an RGB beam combiner on an aluminum oxide platform, leveraging Mach-Zehnder modulators (MZM) and multimode interference (MMI) structures to manipulate light intensity and achieve precise color control. The combiner design incorporates wavelength-specific gratings to radiate red (635 nm), green (520 nm), and blue (452 nm) light into far field at an exact propogation angle. MZMs control the intensity of each wavelength, allowing dynamic color tuning by modulating the beam interference. This signal can serve as the basis for a pixel building block in display technologies, offering flexible color manipulation at the pixel level.