MIRTHE targets new multilevel-modulation all-monolithic integrated TX and RX Photonic Integrated Circuits (PICs) able to achieve 100-400 Gb/s aggregated speed on a single wavelength. This project is motivated by:- the reduction of cost and power consumption of 100Gb/s transmission equipment,- the need of future-proof component technologies for next generation terabit networks.Chips will be packaged and driven at 28 and then 56 GBauds to realize first PIC-to-PIC Terabit range transmissions.The innovation introduced by the monolithic integration of RX and TX with novel vector EAM-based sources should bring a real breakthrough in cost, size and consumption of Terabit components.The specific objectives are:- Demonstration and mastering of a monolithic integration technology of InP-based TX and RX chips suitable for handling 100Gb/s QPSK-type modulation formats,- Demonstration of a future-proof approach by enhancing the bit rate to 200 Gb/s and providing concepts up to 400 Gb/s on a single fiber and wavelength,- Module packaging of the TX and RX PICs with driving electronics,- Demonstration of PIC to PIC transmission at 100 and 200 Gb/s,- Simulations at the device and system levels to identify capabilities and limitations and to contribute to specifications.The innovations claimed are:- Small size TX chips suitable for multi-level coding (QPSK, QAM), based on phase switching in EAM-based PICs,- Fully integrated RX chips demultiplexing both polarizations of the incoming light signal (DP-QPSK),- Evaluation and prototype fabrication of novel monolithic coherent receiver types, applying multiport approaches,- Demonstration of low-power low-footprint multi-level coding TX and RX,- Coplanar coherent receiver package with gain-controlled linear electrical amplifiers.- Demonstration of 200 – 400 Gb/s capability of InP-based TX and RX PICs- Integrated approach for photonic circuit numerical modelling and design.