Ultracompact RGB (de)multiplexer based on a silicon nitride dual-segmented MMI.

The RGB (de)multiplexer is a key component in laser display systems and demands advanced design solutions that achieve high efficiency within a small form factor. Here, a CMOS-compatible silicon nitride (SiN) visible light photonic integrated circuits (PICs) platform is employed to successfully demonstrate an ultracompact RGB (de)multiplexer, featuring a footprint as small as 86 × 2.3 µm2. Leveraging a novel, to the best of our knowledge, dual-segmented multimode waveguide design, the device achieves a low insertion loss of ~1-2 dB at target wavelengths and sets the stage for monolithic integration of laser sources on the same PIC chip. This breakthrough further paves the way for the development of integrated, miniaturized CMOS-compatible RGB light engines offering superior brightness, high resolution, and a wide field-of-view. We anticipate that our design can contribute significantly to the development of immersive AR/VR/MR display technology, while simultaneously extending its impact into sensing and visible light communication applications.