Abstract

Increasing data traffic requires ever-higher-speed links between chips, boards and multi-chip modules. Electrical interconnects are rapidly reaching their limits in terms of data rate and density. The high bandwidth and low cross-talk associated with optical methods can be exploited to replace existing electrical interconnects within some systems. Before III-V and/or II-VI optoelectronic (OE) devices can be utilized within silicon-based electrical processing systems, the problem of hybrid integration must be overcome. Hybrid electrical/OE packaging therefore, is a critical enabler of optical interconnects within electrical systems. We study the impact of electrical packaging on high-speed optical interconnects. This study is made possible by a new OE system simulation tool created within fREEDA, a multi-physics modeling environment. The multi-physics capability of this tool is demonstrated through the implementation of electrical/thermal laser-driver models [1], electrical/thermal/optical laser models and electromagnetic/thermal package models. Figure 1 shows the VCSEL output with thermal rollover. Thermal rollover is modeled using leakage current and temperature dependent gain [2]. By combining these models we are able to perform a comparative study of packages such as printed wiring board, thin film, and flip-chip bonding for VCSEL-array-based interconnects. We will consider high-speed operation at 1Gbps, 5Gbps, and 10Gbps and we will quantify the performance of the overall interconnect system in terms of optical signal fidelity. Optical power for thin film and flip-chip packages @1GBps is compared in figure2 using a simple laser Driver [1]. Results of figure 2 demonstrate switching noise inherent in simple driver configuration. Package crosstalk is more obvious in thin-film package compared to flip-chip. Effect of bias level on VCSEL chirp is demonstrated in figure 3. Wavelength chirp reduces at higher biases. Also possible within fREEDA is the simulation of end-to-end free-space optical systems. This capability will be demonstrated by extending the package study to include the propagation of the (space-time domain) optical signal through components such as micro lenses, gratings, and beam-splitters.

© 2003 Optical Society of America