Fiber specklegram-multiplexed sensor

Abstract

In this study, several multiplexing techniques have been combined to achieve a fiber specklegram multiplexed sensor. Using a single CCD camera as detector, two lasers of different wavelengths have been launched into two multimode polymer optical fibers and then combined through a 2 x 2 coupler before their interrogation. Both coupler exit fibers have been projected to different CCD positions and by analyzing each color of the video sequence, the four fiber channels can be independently obtained. In addition, the speckle sensitivity has been also studied analyzing different properties of speckle patterns such as their contrast or the speckle size. The achieved results will be very useful to the development of new fiber specklegram sensors with several sensing areas using only a CCD camera as detector, making possible low cost sensing devices.