{"id":1959,"date":"2026-05-20T03:28:53","date_gmt":"2026-05-20T03:28:53","guid":{"rendered":"https:\/\/photo-detector.com\/?p=1959"},"modified":"2026-05-20T03:32:14","modified_gmt":"2026-05-20T03:32:14","slug":"fotodioden-rauschanalyse","status":"publish","type":"post","link":"https:\/\/photo-detector.com\/de\/photodiode-noise-analysis\/","title":{"rendered":"Photodiodenrauschen: Schrotrauschen vs. thermisches Rauschen erkl\u00e4rt"},"content":{"rendered":"\n

If you\u2019ve ever stared at your oscilloscope wondering why your signal looks so damn noisy even though the light level seems decent, you\u2019re not alone. Most analog circuit engineers I talk to eventually hit the same wall: photodiode noise<\/strong> is eating their SNR for breakfast.<\/p>\n\n\n\n

After years of helping customers optimize detection circuits here at BeePhoton, I\u2019ve learned one thing above all\u2014understanding the difference between shot noise<\/strong> and thermal noise<\/strong> isn\u2019t just academic. It\u2019s the difference between a design that works in the lab and one that actually performs in the field.<\/p>\n\n\n\n

Today I\u2019m going to walk you through exactly how these two dominant photodiode noise<\/strong> types behave, when each one takes over, and what you can actually do about it. No fluff, no perfect textbook answers\u2014just the stuff we\u2019ve learned the hard way.<\/p>\n\n\n\n

Why Photodiode Noise Matters More Than You Think<\/h2>\n\n\n\n

Let\u2019s be honest. You didn\u2019t come here for theory. You\u2019re probably trying to squeeze a few more dB of SNR out of a lidar receiver, a medical sensor, or some industrial optical measurement system.<\/p>\n\n\n\n

Every nanoamp of photodiode noise<\/strong> current directly limits your minimum detectable signal. And here\u2019s the part many engineers miss: the dominant photodiode noise<\/strong> source changes depending on your operating conditions. What works at high light levels falls apart at low light levels, and vice versa.<\/p>\n\n\n\n

Our Si PIN photodiodes<\/a><\/strong> regularly get used in applications where customers are chasing sub-picoamp noise floors. Getting there means you have to know your enemy.<\/p>\n\n\n\n

The Main Types of Photodiode Noise<\/h2>\n\n\n\n

There are four noise sources you\u2019ll usually wrestle with in a photodiode circuit:<\/p>\n\n\n\n