The impact packaged device planarity has on insertion loss in a DMD based optical networking system



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Texas Tech University


This paper will effectively show whether or not packaged die planarity has an impact on optical system insertion loss and also determine whether or not the die attach systems compromises system performance criteria due to reduced packaged die planarity. A new and important application for Texas Instruments Incorporated Digital Micromirror Device (DMD^M) is in optical switching where it can play a role in dynamic network reconfiguration and signal grooming in the DWDM technology. Using the DMD™ will help the Dense Wavelength Division Multiplexing (DWDM) technology reach a high number of wavelengths in the optical fiber, thus increasing the overall bandwidth of the optical fiber. To obtain this goal, many parameters must be considered. One key performance parameter in this application is insertion loss. Insertion loss is the light power that is lost going from one optical fiber to another as it passes through key optical components.

In this work, the impact of device planarity on insertion loss for a particular system configuration is investigated. Calculating the radius of curvature from the topography of the packaged die will enable the user to determine the mathematical approximation of the impact of planarity on insertion loss. Interferometric data obtained by measuring the packaged devices are used to create a simple model for the optical performance. The insertion loss of the DMDTM in a generic fiber optic system can be estimated. The distributions of two different die attach systems are compared from an optical performance perspective.