Integrated photonics for imaging: novel sources, architectures and applications

Abstract

Integrated photonics is considered a promising technology to tackle many current technological bottlenecks including data communication, computation, sensing and healthcare. Consequently, significant efforts have been dedicated to the study of integrated optical devices and systems for these applications. However, despite its disrupting potential, the use of integrated photonics for imaging applications has only recently started to be considered, and its scope has mostly been limited to Light Detection and Ranging (LIDAR) for autonomous driving. This thesis deals with the development and experimental demonstration of integrated optical systems for imaging applications. In particular, in the first part of this thesis we address the realization of arrays of silicon LEDs (both free space coupled and waveguide coupled) in CMOS photonics processes. We show that such sources can be used to realize compact lensless holographic microscopes, and we leverage CMOS integration to demonstrate a novel reflection holography architecture. We also show how silicon waveguide coupled light sources can be used to realize truly monolithic, highly multiplexed refractive index sensors at low cost and small form factor. In the second part of this thesis we explore the scaling limits of traditional Optical Phased Arrays (OPAs) for beam steering applications and study the use of non-uniformly spaced OPAs to circumvent such limitations. This thesis lays out novel light sources, architectures and applications that leverage silicon photonics platforms to realize compact, low cost and high performance imaging systems. This serves as a stepping stone toward the transformation of currently expensive and specialized imaging systems into the consumer market.