Photosensors or photodetectors are sensors of light or other electromagnetic energy. Optical detectors, which are mostly quantum devices in which an individual photon produces a discrete effect.PD-InGaAs Series Photodiodes are high-speed pigtailed InGaAs PIN photodiodes designed for light detection in the near infrared range. These photodiodes provide wideband characteristics at a low bias voltage, ideal for use in optical communications, high-speed photometry, and monitoring applications.