A Study On The Wave Demultiplex Technology With Dense Multiple Volume Holographic Gratings

Optical fiber communication is one of the most important technologies, which is supporting the rapid growth of communication, and is becoming the prop of modern communication. WDM technology is an effective method to enlarge the capacity of optical fiber communication and to use fully optical fiber bandwidth. However, the properties of WDM devices barely approach the application demand. With the fast development of WDM, it is desired to obtain superior quality and denser WDM device.In this thesis, by contrasting, I indicate some advantages and disadvantages of several kinds of WDM respectively, and study thoroughly on a new method to make demultiplexing device with volume holographic technology. Meanwhile I discuss some issues about this kind of WDM such as design principal, facture method and its properties.Properties of volume holographic grating such as diffraction efficiency, angle and wavelength selectivity are discussed in detail based on coupled-mode theory. The fundamental principle that photorefractive volume grating is used as a wave filter for WDM is illustrated. The pacing technology in making the WDM device such as selecting record material, making sure recording geometry and exposure time are analyzed further. The research conclusions are as follows: The Fe doped LiNbO3 should be considered at first as holographic recording material in our system due to its outstanding advantage properties. Compromise consideration, a ordinary-polarization and 90?geometry recording configuration must be applied because such arrangement has the highest selectivity sensitivity, good uniformity of diffraction efficiency and relatively simple system. In order to gain maximum diffraction efficiency, it is necessary to take a suitable beam intensity ratio according to coupling coefficient if the coupling between two writing beams. Not only are the equations of optimum beam ratio and corresponding maximum diffraction efficiency deliberated, but also the experiment scheme to measure them is designed. To gain possible uniform diffraction efficiency, the effects including the relation about recording geometry with effective electro-optical coefficient and space charge field, wavelength of diffraction beam and diffraction angle and so on are taken into account further besides optical erasure, and more perfect exposure time is deliberated based on recurrence method.Because the expensive tunable laser is not available in laboratory, the high-luminosity halogen lamp is considered as the multiplex photosource, at results, the cost become lower and the program keep more practicable. A experimental scheme of 16 channels wave demultiplex based on volume holographic technology is designed, and its channel capacity, noisiness, cut-in loss, isolation and storage persistence are analyzed. Finally, the application promise of this new technology is anticipated.