Predictive models for power dissipation in optical transceivers

Abstract

Power dissipation in optical networks is a significant problem for the telecommunications industry. The optical transceiver was selected as a representative device of the network, and a component based power model is developed for it. This model indicates that there are three key power dissipating elements in an optical transceiver: the electrical MUX/DEMUX, the thermoelectric cooler (TE cooler), and the modulator driver amplifier. First, the electrical MUX/DEMUX materials and functionality are investigated, and a circuit model is developed to simulate the MUX/DEMUX using both CMOS and MOSFET Current Mode Logic circuit topologies. The SPICE simulations use future technology generation process cards from the Berkeley Predictive Technology model, and enable the simulations to predict the power dissipation of the MUXs in the future. The results of these SPICE simulations show that improvement in technology generations significantly reduces the power dissipation of the MUX circuits. The TE cooler is then examined and a MATLAB model is developed to predict the thermodynamic flow through a packaged laser and TE Cooler. The MATLAB simulations of this model show that although materials with lower thermal conductivity result in more cooling power for the TE cooler, they also significantly raise the overall temperature of the laser. Therefore, lower thermal conductivity is not the best way to reduce power dissipation in the TE cooler. Together these physical models give a better understanding of the factors that will most influence the power dissipation optical transceivers in the future.