Fiber-Wireless-Fiber Fully Integrated D-Band System (FiWiFi)

• Applicants: Professor Dr.-Ing. Dietmar Kissinger; Professor Dr.-Ing. Christian Waldschmidt
• Subject Area: Electronic Semiconductors, Components and Circuits, Integrated Systems, Sensor Technology, Theoretical Electrical Engineering
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 427778912

Current opto-electronic wireless bridges consist of hybrid systems where optical and electronic parts are different MMICs packaged through micro-wires or flip-chip bonding and communicating each other through a mother board where the antenna finds place. This reflects mostly into losses and bandwidth reduction, limiting the performance in terms of wireless link speed. This proposal aims to overcome those practical problems through a full integration onto a single chip of the entire chain, from the fiber to the antenna. In particular, the project aims at exploiting a new technology platform by IHP allowing the integration of high-speed optical components as photodiodes and Mach-Zehnder modulators, high rf-circuits as mixers and amplifiers and on-chip LBE-based antennas. The proposal aims at exploiting the new technological feature of structuring the metallic layer on top of the silicon bulk in combination with localized backside etching of the bulk.Considering the typical data-rate within fibers in a data center the technological frequency limits and the antenna size, the D-Band has been selected. The wide frequency band between 110 and 170 GHz from one side allows very high data-rates, but from the other pushes to the limit the design of electronic circuits, optical components and antennas. The following main objectives are addressed:• Opto-electronic transmitter and receiver speed: the speed of the current versions of both opto-electronic receiver and transmitter is not yet enough to support the desired bandwidth. Faster TIAs and MZM’s drivers will be designed.• Transceiver and antenna bandwidth: The 60 GHz bandwidth centered at 140 GHz results in 43% relative bandwidth. On top of that, the D-Band is very close to the technological frequency limits. • Communication distance: The targeted application requires a wireless link up to some meters. Given the high free space path loss at the selected frequency band, the limited achievable output power and noise figure and the low typical gain of on-chip antennas, such a distance turns to be very challenging. The applicants address all the mentioned challenges by proposing a fully integrated two-chip approach, where a Tx and a Rx chip communicate wirelessly. The main strength of this system is the full integration, from the fiber to the antenna on the Tx side and vice versa. With the help of self-complimentary multimode antennas, sufficient antenna gains at simultaneously large bandwidth in various directions of radiation are aimed at, realized by antennas exploiting the new technological feature of the combination of localized backside etching and a structured metallic layer on top of the silicon bulk.

• DFG Programme: Research Grants