Quadrant avalanche photodiodes (QAPDs) cannot be made with a perfect transition region. We are pursuing development of several optical divider approaches to narrow the effective transition region of the RCA Juction-side divided QAPD, a superior device except that it has no response in the transition region. This divider will maximize the slope factor and minimize optical losses. Optical divider approaches include the total internal reflection prism divider, the etched silicon reflective divider, and the binary optics quadrant divider. The nature and progress of this work and the test results are reported.
Samuel I. Green, Samuel I. Green,
"Optical dividers for quadrant avalanche photodiode detectors", Proc. SPIE 1417, Free-Space Laser Communication Technologies III, (1 June 1991); doi: 10.1117/12.43779; https://doi.org/10.1117/12.43779