The work in the first 30 months mainly focused on designing and fabricating a first SiN and InP run, including designs for Demonstrators, developing the µTP technique further, and designing a second run. Initial building block and Demonstrator results were obtained.
Novel components have been designed, to be implemented on INSPIRE runs. An efficient and tolerant coupler, to convert the optical mode from the SiN to the InP waveguide, has been designed and implemented on the second INSPIRE run. Electrodes have been optimized for high-speed operation and a 100-GHz modulator has been designed. A thermal analysis has been done to design closely-spaced SOA arrays, for dense integration.
The fabrication of the first SiN run has been completed and the waveguides and building blocks have been characterized. These served as a benchmark for further Demonstrator design and an updated second SiN run, which is now taped out. The fabrication of the first InP run suffered from open circuits in the electrical contacts, preventing us from characterizing the active components, such as SOAs and modulators. Passive components for testing mode conversion and insertion loss are being printed for further characterization. A new process flow has been designed for the second InP run.
With respect to the µTP technique development, we have realized successful printing of InP coupons on SiN with an accuracy better than 1 µm at sample scale. We have started preliminary work for wafer scale printing.
The Demonstrators, i.e. fiber sensor interrogator, microwave photonic engine, and datacenter switch, have been designed for the first and second run. Using the SiN dies from the first run, complemented with legacy InP coupons, a 20-GHz FMCW, 2-kHz optical linewidth fully integrated laser was experimentally shown, with beyond-state-of-the-art performance. The passive SiN filters hit the target metrics. The switch was packaged, but had too limited gain for system demonstration.
With respect to exploitation, the initial InP process to realize coupons for µTP has been transferred to and set up at SMART Photonics. Some INSPIRE partners are key participants in the new KDT photonixFAB Pilot Line, laying out the path for further TRL scaling of the µTP process, beyond INSPIRE targets. A benchmark study was conducted to make sure the INSPIRE target metrics are (still) relevant and lead to a competitive technology and Demonstrators.
