Lithium niobate on insulator (LNOI) is one of the most promising emerging platforms for photonics integrated circuits (PICs) that comprises a unique set of interesting optical properties such as: a high electro-optic (EO) coefficient, high intrinsic 2nd and 3rd order nonlinearities, and a large transparency window (350 nm - 5500nm). Lithium niobate (LiN) has attracted a lot of attention since the 1970s, however, most of its industrial success has been limited to devices made from bulk LiN crystals in the form of free-space or fiber-coupled components using ion-implanted waveguides. Recent advancements in bonding of single crystal thin films of LiN onto silicon substrates (LNOI), opens a new avenue to explore the advantages of LiN in the context of PICs and to benefit from their miniaturization, cost reduction, scalable manufacturing and integration.
In the LNIO platform, waveguides are fabricated using reactive ion etching (RIE) in a LiN thin film which allows for significantly higher refractive index contrast () compared to traditional waveguides made by ion implantation technology in bulk crystals (). This allows to reduce the optical mode volume by more than ~100x. Such high confinement not only results in more efficient and faster modulators but also in significantly smaller bending radii and PIC footprints, which, ultimately enables designing complex PICs with tens of components in a millimeters-size chips. In an LNOI platform we can combine high performance active EO components such as modulators, phase shifters and tunable cavities with unique optical nonlinearities at a wide range of wavelengths to achieve truly novel functionalities and PIC designs that are beyond the capabilities of any PIC platform commercially available today.
In this talk I will present the recent progress at CSEM toward developing an EO and nonlinear PIC platform based on LNOI. We start by reviewing the advantages of LNOI platform for various application areas such as telecom, optical signal processing, programmable PICs, LiDAR, spectroscopy, quantum information processing, and nonlinear photonic. Then we will review how LNOI platform fits within the industrial PIC ecosystem and how it compares with other PIC platforms such as Si, SiN and InP. We then discuss the challenges in fabricating high quality photonics circuits in LNOI and will review CSEM’s recent results in design, fabrication, and testing of high quality LNOI photonic circuits. Next, we briefly review few successful example and experiments performed by CSEM or in collaboration with other groups in the areas of nonlinear photonics and quantum information processing. Finally, I will present the future perspectives of our LNOI platform including the process design kit (PDK) library and the means that interested parties can access our platform as a pre-commercial foundry service.
Dr. Amir H. Ghadimi is currently a senior scientist and a group leader at the Swiss Center for Electronics and Micro/nano technology (CSEM). He is currently leading the efforts at CSEM in the areas of PICs and PIC based sensing where together with his team they are developing two PIC platforms based on SiN and LNOI. He obtained his PhD. in electrical engineering in 2018 from the Swiss Federal Institute of Technology (EPFL). His PhD research focused on quantum optomechanics, precision sensing and applications of high Q optical and mechanical resonators. He is the recipient of Swiss national funding (SNF) Bridge discovery grant (2020), Swiss Physical Society (SPS) 2019 young scientist award, Swiss Nanotechnology best PhD award (2018) and European frequency and time forum (EFTF) best paper award (2018).