SiN foundry platform for high performance visible light integrated photonics

We present a high performance silicon nitride photonic integrated circuit platform operating at visible wavelengths, accessible through the commercial foundry, LIGENTEC. Propagation losses were measured across the visible spectrum from 450 nm to 850 nm. For wavelengths above 630 nm, losses were <1 dB/cm in TE and <0.5 dB/cm in TM. Additionally, sets of single mode waveguide-coupled ring resonators across three separate chips were tested and analysed. A peak intrinsic Q factor of 3.69 x 106 was measured for a single resonance at similar to 635.3 nm, with an average value of 2.28 x 106 recorded over 10 peaks in a 3 nm tuning range. Analyses of the loss and coupling, as functions of bus-ring coupling gap and waveguide width, are also presented. High confinement, low loss devices realised on the chip-scale in a wide-bandgap material like silicon nitride are increasingly important for the next generation of integrated optical devices operating at visible wavelengths.