Home-made N-channel fiber-optic spectrometer from a web camera

This paper demonstrates the high potential of a web camera to be utilized as a low-cost multichannel fiber-optic spectrometer suitable for either educational or quality-control purposes in small and medium enterprises. The key idea is to arrange N input optical fibers in a line and position an external dispersive element to separate incoming optical beams into their associated spectral components in a two-dimensional (2D) space. With a commercial web camera, each set of the spectral components is imaged through a plastic lens onto the 2D image sensor of the web camera. For the demonstration, a five-channel webcam-based fiber-optic spectrometer is implemented where each channel is calibrated by selected reference light sources. The constructed spectrometer can perform wavelength analysis of the spectral irradiance in the range of 400 to 655 nm. Experimental results also show that peak operating wavelengths of five light-emitting diodes and a laser pointer can be determined with a wavelength measurement error of less than 10.5 nm. The total cost of the webcam-based five-channel fiber-optic spectrometer is only approximately US$92.50 and effectively performs to the desired results.