The sensor is mounted on a PCB, as shown, with all the necessary circuitry to convert incident wavelength to an output voltage. The voltage is directly proportional to wavelength in the range of 450nm to 900nm. The output is independent of illumination. The circuit provides switched gain controls to accommodate various output requirements. As an example, a typical output is 1.7 volts for a wavelength of 670nm, with a gain setting of 5. The output provides typical information and must be calibrated against known sources of accuracy. Resolution of 0.1nm is possible. The circuit requires ±15 volts and consists of two logarithmic amplifiers and a ratio calculator. The sensor is mounted on a temperature monitor for reference.
Applications include laser monitoring, matching of LEDs and other light sources.