Static laser speckle suppression using liquid core fibers

Static laser speckle suppression using multimode fibers has practical limitations as the technique requires an extremely long fiber to achieve an acceptable speckle contrast. An effective method based on liquid light guides was developed in this study to suppress laser speckle. In this study, a speckle simulation model of the liquid light guide was established for numerically calculating the speckle contrast without solving the analytical solution of the photon diffusion equation. The obtained simulation results were compared with the experimental results for the dependence of speckle contrast on the required length and numerical aperture with different liquid core types of liquid light guides. A speckle contrast of 12% and a speckle suppression efficiency of 5 was achieved at the end of a 2.4 m long liquid light guide. For the same fiber length, liquid light guides were found to suppress speckle more efficiently when compared to multimode fibers.