WP4 is closely connected to the process and substrate development tasks in WP3. The sub tasks in 4.2 related to laser integration and modulators using non-silicon materials require multiple iteration steps between work packages 3 and 4. The outcome of WP4 provides PIC designs that allow for the realization of PIC100 based demonstrators in WP5 and the development of building blocks that will be used to define the PIC200 technology. The PIC200 related outcome benefits especially from the usage of new simulation and design tools created in task 4.3 for modelling and evaluating the building block behaviour on circuit and system level. In order to demonstrate the application use cases in WP5, PICs are combined with high-speed RF-EIC designs from task 4.5, with a focus on driver and TIA circuits. The assembly of WP5 demonstrators leverages the methods for the assembly of optical packages developed in task 4.4. The objectives of WP4 are:

• O4.1: Designing basic circuits (PIC100/PIC200 and EIC) and/or building blocks that are all essential parts of silicon photonics transceivers.
• O4.2: Paving the way to silicon photonics technologies (PIC100 and PIC200) for other European companies by developing a complete design flow in silicon photonics, to reinforce the Europe silicon photonics ecosystem.
• O4.3: Providing full European sovereignty in silicon photonics all along the value chain with suitable and specific packaging solutions.
• O4.4: Demonstrating that the silicon photonics evolution to 200 GBd is reachable for Europe by exploring and verifying capabilities of PIC200 technology through series of building blocks proofs of concept.
• O4.5: Demonstrate novel circuits for transceivers and simultaneously offer significant/drastic reduction of power consumption as well as reduction of metal (mainly copper and aluminium) usage for their future hostsystems.