High-speed resonant-cavity avalanche photodiodes with separate absorption and multiplication regions

ABSTRACT The performance ofconventional photodiodes is limited by an intrinsic tradeoffbetween quantum efficiency and bandwidth.We have successfully demonstrated that resonant-cavity photodiodes can simultaneously achieve high quantum efficiency and widebandwidth. The resonant-cavity approach lengthens the effective absorption thickness through multiple reflections between twoparallel mirrors. Previously, it has been shown that resonant-cavity, separate-absorption-and-multiplication (SAM) avalanchephotodiodes (APDs) exhibit high peak external quantum efficiency ( 75% ), lowdark current and low bias voltage ( <15V). In thispaper, we describe the frequency response ofresonant-cavity AlGaAs/GaAs/JnGaAs SAM APDs. A unity-gain bandwidth of23 0Hzand a high gain-bandwidth product of 130 0Hz have been achieved. Also, low multiplication noise characteristics ( O.2avalanche photodiodes, resonant cavity, separate absorption and multiplication, high-speed, quantum efficiency, gain-bandwidth product, noise