Abstract

Laser beam scanning (LBS) is currently one of the most compact solutions for augmented reality (AR) displays. State-of-the-art LBS displays still rely on laser modules with three separately mounted red, green and blue (RGB) lasers and (miniaturized) free-space optics to combine the separate laser beams.
Leveraging recent advances in visible-light photonic platforms based on Silicon Nitride (SiN) and maturing heterogeneous integration technologies, we propose an integrated RGB laser engine on a single photonic integrated circuit (PIC).
This integrated solution not only reduces the size of the laser module, but also allows us to use external modulation to reduce the temporal coherence of the laser light. This high coherence of laser light often results in unwanted interference, causing speckle noise in the image. Additionally, we explore an alternative approach to mitigate this unwanted speckle effect: by integrating multiple laser sources in parallel, we can average out the speckle induced by each laser, but also increase the display's resolution and field of view (FOV).