Bandwidth Broadening of the Photodetector Signal Path

L. Opalski, K. Opalska (Warsaw Univ. of Techn., Poland)

The paper considers bandwidth oriented optmization of an analog signal path, composed of an infrared photodetector, an amplifier and a transmission line connecting the two. To investigate influence of design variables upon bandwith a simplified model of the signal path is analyzed first. Several design scenarios are considered, including separate line length and load resistance settings, but also insertion of a simple LC corrector. Trade-offs between bandwidth and passband ripple level are investigated numerically, visualized and discussed. Finally, it is confirmed that appropriate selection of the connection length, and or passive corrector can result in substantial bandwidth increase for a realistic model of an infrared photodector, wide band gain-block and a flexible stripline connection.