Packaging Aspects of Photodetector Modules for 100 Gbit/s Ethernet Applications

Packaging is a major problem at millimetre-wave frequencies approaching 100 GHz. In this paper we present that insertion losses in a multi-chip module (MCM) can be less IL < 0.6 dB at 100 GHz. The paper also analyzes in detail resonance modes in the packages. The characteristic of conductor-backed coplanar waveguides (CBCPWs) with vias is accurately analyzed using 3D electromagnetic (EM) simulation over a wide frequency range. Patch antenna mode resonances are identified as a major origin of resonances in simulated and measured transmission characteristics of the CBCPW with vias. Based on EM simulations, we propose several optimized arrangements for vias and bonding wires placement, to efficiently suppress the resonances and achieve excellent transmission performance of the PD module packaging. Based on our simulated results we postulate that it is possible to obtain resonance-free electrical transmission in the PD package with IL < 0.6 dB over a frequency from DC to 110 GHz.