Heterogeneously integrated silicon-conductive oxide MOSCAP microring modulator array

In pursuit of energy-efficient optical interconnect, silicon microring modulator (Si-MRM) has emerged as a pivotal device offering an ultra-compact footprint and capability of on-chip wavelength division multiplexing (WDM). This paper presents a 1 × 4 metal-oxide-semiconductor capacitor (MOSCAP) Si-MRM array gated by high-mobility titanium-doped indium oxide (ITiO), which was fabricated by combining Intel's high-volume manufacturing process and the transparent conductive oxide (TCO) patterning with the university facility. The 1 × 4 Si-MRM array exhibits a high electro-optic (E-O) efficiency with Vπ⋅L of 0.12 V⋅cm and achieves a modulation rate of (3×25 + 1×15) Gb/s with a measured bandwidth of 14 GHz. Additionally, it can perform on-chip WDM modulation at four equally spaced wavelengths without using thermal heaters. The process compatibility between silicon photonics and TCO materials is verified by such industry-university co-fabrication for the MOSCAP Si-MRM array and demonstrated enhanced performance from heterogeneous integration.