LED wavelength determination sensor system with BiCMOS triple junction photodetector

A sensor system for the wavelength determination of LEDs is presented. The used sensor is a triple junction photodiode which needs no external filters. The sensor is implemented in a standard BiCMOS process without any process modifications. The sensor system is optimised for low analogue complexity and compatibility with mass production in a cost-sensitive environment. A proof of concept sensor system is presented which demonstrates the ability to determine the wavelength of LEDs. The measurements evaluate the linearity of the system and the possibility for a fast calibration in the production environment.