Abstract

Recently we have proposed the use of multimode optical fibers for optical sensing utilizing speckle hologram techniques. In this paper the feasibility of using the fiber speckle hologram techniques for optical switching is demonstrated. Traditional methods of optical switching employ mechanical means to make or break optical paths, or non-mechanical electrooptical (EO) switches based on polarization rotation. The mechanical methods are slow (1-100 ms). Though the EO switches are faster they are bulky and cumbersome to construct and use. To overcome these disadvantages we propose the use of fiber specklegram as a less clumsy and faster optical switching technique. A hologram is formed using a speckle pattern and a spherical reference beam. The transmission hologram thus formed is recorded using a LiNbO₃ crystal. On illumination by just the speckle field, the hologram can partially reconstruct the reference beam yielding some information encoded in the speckle field. The reconstruction of the hologram is sensitive to changes in the speckle field. By utilizing this property, and multiplexing more than one specklegram an EO switch has been designed. The design and uses of such a switch are discussed, and the experimental results are presented.

© 1991 Optical Society of America