Three-terminal optoelectronic component with improved matching of electric field and photocurrent density

Abstract

A three-terminal avalanche photodiode provides a first controllable voltage drop across a light absorbing region and a second, independently controllable, voltage drop across a photocurrent amplifying region. The compositions of the absorbing region and the amplifying region may be optimized independently of each other. In the amplifying region, p-doped and n-doped structures are offset from each other both horizontally and vertically. Directly applying a voltage across a controlled region of the photocurrent path increases avalanche gain by shaping the electric field to overlap the photocurrent density. The resulting high-gain, low-bias avalanche photodiodes may be fabricated in integrated optical circuits using commercial CMOS processes, operated by power supplies common to mature computer architecture, and used for optical interconnects, light sensing, and other applications.