APECS – European pilot line for advanced packaging and heterogeneous integration
Photonic Integration – Optical Transmitter for HPC
Target
Development of an O-Band 4 × 200 Gbps transmitter with high shoreline density for HPC I/O. The demonstrator targets a hybrid-integrated photonic–electronic high-speed transmitter module based on InP EML array and driver chiplets assembled on a common interposer platform, including electrical and optical interfaces.
Innovation
Hybrid-integrated ultra-high-speed transmitter module combining InP photonic and electronic components with advanced interconnection technologies such as photonic wire bonds and polymer-based RF flexlines. Enabler for high-density integration, scalable multi-channel optical coupling, and high-bandwidth electrical interconnects.
Approach
- InP EML 4-array chiplet (4 × 200 Gbps PAM4)
- InP HBT-based EML driver chiplets
- Polymer-based RF flexlines for high-speed electrical interconnection
- Photonic wire bonds for optical coupling to a 4-fiber array
- Silicon-based interposer hosting all components
RF flexlines with bandwidths exceeding 200 GHz are used for the electrical connection between driver and EML, enabling high-speed signal transmission.
The interposer fulfills three key functions, mechanical carrier for chiplets and fiber array, electrical routing between drivers and connectors, and efficient thermal management and heat dissipation.
Progress
- Reduction of EML array pitch from 640 µm to 375 µm (target: 250 µm)
Demonstrated modulation speeds up to 290 Gbps PAM4 - Driver amplifier bandwidth > 150 GHz
Output power up to ~12 dBm with distributed amplifier topology - RF flexlines with bandwidth > 200 GHz realized
- Successful multi-channel optical coupling using photonic wire bonds
- Ongoing optimization of optical interface for low loss and low reflection
Partners
- Fraunhofer HHI – Photonic chiplet development, EML arrays, RF flexlines
- Leibniz Institute FBH – Driver chiplet development
- Fraunhofer IZM – Interposer, Photonic Wire Bonding, and hybrid integration
Impact
The demonstrator combines advanced InP photonics, high-speed InP driver electronics, and innovative integration technologies to realize complex photonic subassemblies. It validates the APECS pilot-line capabilities for hybrid photonic–electronic integration and enables scalable high-speed transmitter solutions for HPC and data communication applications.