ADPD188GG Integrated Optical Module Analog Devices ADPD188GG Integrated Optical Module is a complete photometric system designed to measure optical signals from ambient light and from synchronous reflected light emitting diode (LED) pulses. Synchronous measurement offers best-in-class rejection of ambient light interference, both DC and AC. The module integrates a highly efficient photometric front end, two LEDs, and two photodiodes (PD). All of these items are housed in a custom package that prevents light from going directly from the LED to the photodiode without first entering the subject.