Theoretical And Experimental Study On Photorefractive For Optical Cross Connector

Optical switching is basic component in optical cross connector. In this thesis, by contrasting, some advantages and disadvantages of several kinds of optical switching are indicated respectively, and a new method to make optical switching based on volume photographic technology is studied thoroughly. Meanwhile, some issues about this kind of optical switching, such as principle of design and method of facture, are discussed.First, the properties of volume holographic gratings, such as diffraction efficiencies, angle, wavelength and wave front phase selectivity, have been theoretically analyzed by using the couple-wave theory. Especially, a theoretically analysis of wave front phase selectivity has been deduced. The fundamental principle that photorefractive volume grating is used to make optical switching is presented. The key technologies in making the optical switching, such as selection of recording material, method of encode and recording geometry, are further studied. The research indicate that:The superimposed volume gratings have excellent diffraction selectivity, in the condition of using a perfect phase modulator. A diffraction selectivity theoretical analysis method of volume gratings with wave front phase encoding is proposed.The Fe doped lithium niobate (LiNbO3:Fe) should be considered as holographic optical switching recording material at first, due to its available large crystal sizes, long storage lifetime and high diffraction efficiencies, which allow for increased capacity and high angular selectivity.In order to gain maximum diffraction efficiency and highest selectivity sensitivity, an extraordinary polarization geometry configuration should be applied. However, in order to gain good uniformity of diffraction efficiency, an ordinary polarization recording geometry configuration should be applied. The geometry configuration can be decided by channels and encoding methods.A experimental scheme of phase selective 1×3 and N×1 holographic optical switching based on volume holographic technology is designed, and preliminary study of experiment is presented.