A Survey of Methods Using Balanced Photodetection

Balanced photodetection is a commonly used detection method in the lab when an experiment requires increased signal-to-noise. This detection method has many advantages to simply amplifying a signal with an amplifier following the photodiode. In some cases, it can also achieve better noise performance and sensitivity than an avalanche photodiode (APD). It is particularly powerful in its ability to cancel laser noise or “common mode noise” and in its ability to detect small signal fluctuations on a large DC signal. In this application note we explore a wide variety of detection methods utilizing balanced photodetectors and briefly discuss their implementation.