Simple and cost-effective wavelength measurement system using photodiode pair: Applications in fiber coupled light sources

Abstract

Determination of wavelength of any light source plays a crucial role for the application areas. In this work, we designed a simple and cost effective wavelength measurement system depending on two photodiodes and an amplifier circuit. Firstly, the wavelength response of the developed measurement system was determined using a monochromator. These results showed that, there was a linear relationship between the wavelength variation and the output of the developed system. Then, the wavelength shift of the laser diodes with respect to the changes in the operating temperature was obtained by a spectrometer. After the determination of the wavelength shift, same measurements were performed using our measurement setup. The wavelength shift of the laser diodes depending on temperature was found to be in a good agreement with the value obtained from the spectrometer measurements and the values given in datasheets of the laser diodes. Finally, the change in the output voltage of the system was investigated according to the optical power of the laser beam. The findings suggest that, proposed measurement system can be a simple alternative for the wavelength measurements and as well as color detection.