When shot-noise-limited photodetectors disobey Poisson statistics

• Main Authors: Rabinowitz, Jacob, Rezaei, Mohsen, Park, Min-Su, Tan, Chee Leong, Ulmer, Melville, Mohseni, Hooman
• Format: Article
• Published: Optical Society of America 2020
• Subjects: QC Physics; TK Electrical engineering. Electronics Nuclear engineering
• Online Access: http://eprints.um.edu.my/25371/; https://doi.org/10.1364/OL.389908

Photodetectors with internal gain are of great interest for imaging applications, since internal gain reduces the effective noise of readout electronics. High-gain photodetectors have been demonstrated, but only individually rather than as a full array in a camera. Consequently, there has been little investigation of the interaction between camera complementary metal oxide semiconductor (CMOS) electronics and the slow response time that high-gain photodetectors often exhibit. Here we show that this interaction filters shot noise and causes noise statistics to differ from the common Poisson distribution. As an example, we investigate a 320 × 256 array of InGaAs/InP high-gain phototransistors bonded to a CMOS readout chip. We demonstrate the filtering effects and discuss their consequences, including new (to the best of our knowledge) methods for extracting gain and increasing dynamic range. © 2020 Optical Society of America