Theory of the GaInAs/AlInAs-doped quantum well APD: A new low-noise solid-state photodetector for lightwave communication systems

We present calculations of the electron and hole ionization coefficients, the excess noise factor, and gain for a doped quantum well APD made from the Al
0.48
In
0.52
As/Ga
0.47
In
0.53
As material systems. The ionization rates are calculated based on an ensemble Monte Carlo method. The effect of all of the device parameters, i.e., doping concentrations, layer widths, and the overall dc bias field, on the carrier ionization coefficients and the deterministic ionization probabilities,
P
and
Q
, is determined. These results in conjunction with recent noise theory results are utilized to determine an optimal device design that provides high gain at very low noise. A complete design including number of stages and individual stage design is presented for the lowest noise, highest gain device realizable in this system. It is anticipated that this device can be used as a new ultralow-noise high-gain receiver in lightwave communications systems.