Fabrication Of Ion-exchanged Channel Waveguides

By the end of 1960s, since the conventional optics system having the big volume, poor stability and difficulty of beam collimation could not satisfy the requirements of optical communication and optical information processing, people hoped to realize integrated optics circuits like the molectron. With the effort on it for several decades, some research productions have already displayed the important functions in the fields of communication, military, power, astronomy, sensors, etc. At the same time, integrated optics has been formed as a new subject with the cross-link of optics and pellicular electronics. The applied fields of integrated optics exist in many aspects. Besides optical communication, sensors, optical information processing and optical computers, they are still infiltrating into other fields, such as material science, optical instrument, spectrum research, etc. According to the emonstration effection of the integrated electronics, many scientists chose the potential researches and developed many kinds of integrated optical devices. Integrated optics, like the integrated electronics, will make a profound change of the information technology.Optical waveguides are the base of the integrated optical circuits. They are the carriers for rapidly transmitting optical signals in large quantities. Asthe elements for restricting and guiding the lights, their essential is that the refractive index of waveguides is higher than that of external medium. In the integrated optical devices, structure and transmission characteristics of channel waveguides are similar with ones of single-mode fiber. Compared with other waveguides, channel waveguides coupled more easily with single-mode fiber and have less coupling loss. Moreover, we also may develop many integrated optics components such as the light branch and the optical waveguide amplifier on the base of the channel optical waveguide. However, because of the complex fabrication techniques of channel waveguide circuits, the application of them is still within the laboratory limits. In order to put the channel waveguide devices into practical use and develop the following experiment, we have emphatically carried on the fabrication and characterization of the channel optical waveguide.In the thesis, the involved contents and present state of waveguides are firstly introduced. They include the structure characteristics, the index profile features, preparing methods, the transmission loss and so on. In addition, it is summarized that some popular techniques about the fabrication of the channel optical waveguides. In this foundation, the method of the silver and sodium ion-exchange was used to prepare the channel optical waveguide in the K9 glass substrates, and what's more, we built a set of coupling and testing system between the optical fiber and the optical waveguide. It is precisely measuring instrument in the optical communication, the optical information processing, optical fiber sensor and the integrated optics research. The testing result indicated that our laboratory has already had the ability to manufacturethe channel optical waveguide. It provides the important basis and the reference value for us to further optimize the design of the channel optical waveguide. At the same time it also makes the good foundation for the following work, such as the light branch and the optical waveguide amplifier. The process of the channel optical waveguides:CleaningAluminium depositionPhotoresist coatingExposition to UT light j Covered filmHHi^— , Photoresist'? Aluminium GlassDeveloping Photoresist Liquid etching of aluminiumiiinBiiiiHiiiiiniiisiiiMiiiiitiimmiiiiiiiiiiiiiiiiiiMiiiiiiiiiiiiffliiiiiiiniimiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiuiiiimiiiHiiiiiiiiIon-ex changeAluminium removalThe process of ion exchange making glass waveguideThe measurement of the channel optical waveguide:(1) Firstly we use the scanning electrical microscope to observe the opticalwaveguide which we have prepared. The following picture is theobservation result of the face shape of the channel optical waveguide.Obviously at the wave guide area face shape is quite neat, and theion-exchange is also very uniform.(2) The waveguide testing system is a set of high accuracy coupling system between the optical fibers and the channel optical waveguide. In fact the realization of effective fiber-optical waveguide coupling is the key of commercialization of integrated optical components from the laboratory. Then we use the end coupling method to test the optical waveguide. The following sketch map is the testing system:visional supervisory equipment1.5U? Semiconductor laserThe testing result is as follows:(c) The light enters the non-waveguide area The facula of this momentObviously we have basically succeeded in fabricating the channel opticalwaveguide .The transmission facula after waveguide area has been well restrained and its intensity is very strong. However the transmission facula after non- waveguide area has a big size because of dispersing in the transmission, and the intensity is also weak. At the same time, by the measurement and analysis to the optical waveguides with different craft parameters, we have summarized the corresponding relations of the waveguide characteristics such as width and the craft parameters. In order to distinguish the facula pattern, we also designed a set of high accuracy coupling test system between the optical fibers and the channel optical waveguide.These experimental results and experience provide the important basis and the reference value for us to further optimize the design of the channel optical waveguide. At the same time it also makes the good foundation for the following work such as the light branch and the optical waveguide amplifier .