Foundry Developments Toward Silicon Nitride Photonics From Visible to the Mid-Infrared

Photonic integration technologies have spread in the past decade by means of foundry models that mirror the electronic-integrated circuit industry developments of the past century. Several monolithic technologies exist, based on silicon and III-V semiconductors. In this paper, we discuss the current state and forthcoming developments of open access photonic foundries whose technology platforms are based on silicon nitride material. The paper presents various silicon nitride technologies and foundries, alongside with access models supported by generic integration and process design kits. Technical features, enabled by different micro-fabrication processes and tools are summarized. Application examples and developments of forthcoming incorporation into these platforms are outlined.