A Moderate Confinement O-, S-, C-, and L-Band Silicon Nitride Platform Enabled by a Rapid Prototyping Integrated Photonics Foundry Process

We describe a rapid prototyping process for silicon nitride photonic integrated circuits operating at wavelengths around 1.3 and 1.5 μm. Moderate confinement silicon nitride waveguides and other essential integrated photonic components, such as fiber-chip couplers, microring resonators, multimode interference-based 3-dB power splitters, and subwavelength grating metamaterial waveguides, were fabricated and characterized and are reported. The prototyping platform features a 400-nm-thick layer of silicon nitride grown via low-pressure chemical vapour deposition onto 4” silicon thermal oxide wafers and uses direct-write electron beam lithography to define single mode waveguide structures that exhibit losses of <1.3 dB/cm across the O-band (1260–1360 nm), <1.8 dB/cm across the S-band (1460–1530 nm), <1.6 dB/cm across the C-band (1530–1565 nm), and <0.7 dB/cm across the L-band (1565–1625 nm) for both transverse electric (TE) and transverse magnetic (TM) polarizations. The reported components were compiled into a process design kit to accompany the platform, which is commercially available through the NanoSOI Design Center operated by Applied Nanotools Inc. with five multi-project wafer runs per year that have fast turnaround times on the scale of weeks rather than months. This provides a route toward the rapid fabrication of silicon nitride chip-based passive and thermo-optic active photonic devices with critical resolution down to 120 nm, making it an attractive solution for entry-level designers, device innovators, and small companies looking to incorporate integrated silicon nitride circuits into early-stage applications of silicon photonics.