Study Of Glass Based Ion-exchange Process And Related Optical Waveguides And Components

The glass-based ion-exchanged technology is one of the mature technologies for fabricating PLC (Planar Lightwave Circuit) devices, which can be widely used in the fabrication of PLC optical power splitters, optical amplifiers, WDM (Wavelength Division Multiplexer) and so on, which are all the key components in the optical network. Today, the development of FTTH stimulates the demands of optical network, so the study of glass-based ion-exchanged technology is of great significance.In this paper, we combined the theory of glass-based ion-exchanged technology with the processes. During the transformation of the technology to industry, first, A new electric-field-assisted ion-exchange model for guiding the practical process was proposed. Second, based on the new model, a program for process-analysis was established, which improves the process. Finally, based on the program, the glass-based ion-exchanged single-mode waveguides and related components were fabricated, of which the indices were meet the standard of the related product, and a process-analysis system for the fabrication of glass-based ion-exchanged optical devices was established, which fixed the new model as the core.Basing on the analysis of the traditional electric-field-assisted ion-exchanged model, we studied the similar conditions of the traditional constant-voltage model. It was found that there was an electro-thermal effect in electric field-assisted ion exchange, which would lead the constant-voltage model to an error. We extracted a new characteristic parameter——charge density flux from the traditional ion-exchanged model to establish a new non-thermal model. And we also carried out a lot of experiments to prove the large process tolerance of the new model. The follow-up experiments showed that the new model also could be applied in any electric-field-assisted ion-exchanging processes. The charge-density-flux model has great significance to the control of practical processes and the choice of process parameters.One of the most practical technologies in glass-based ion-exchanges is Ag+-Na+ ion exchange, which contains thermal ion-exchange and electric-field-assisted ion-exchange. Between them, the process control of the electric-field-assisted ion-exchange is one of the key technologies. Based on the charge-density-flux model, the analysis method of electric-field-assisted ion-exchanged process is concluded, which controls the process and guides the fabrications of waveguides and devices effectively. The method builds the foundation of the stable and repeatable fabricating technology. In addition, both of the two ion-exchanges have their own bottlenecks, such as "silver lines", uneven heat, turbid molten salt and so on. To solve these problems, in-depth analysis of the problem-roots was carried out, and some new solutions were put forward, to which the proper evaluations were made by experimental comparisons.According to the special needs of ion-exchange, we designed and fabricated the special glass materials for ion exchange and used two-step Ag+-Na+ion exchange basing on the previous work. Basing on the new glass, we fabricated low loss single-mode waveguides of the transmission loss 0.1dB/cm and the coupling loss 0.2～0.3dB to the single-mode fiber under the guidance of the process-analysis program. The fabrication of the waveguides provides an important reference to the fabrication of optical components with high performance. And then 1×8 optical power splitters were fabricated based on the tilt-type-Y-branch-optical-splitter design, the process-analysis system of the waveguide fabrication, the batch-reproducibility experiments and the product-test standards, of which the typical loss was 10.3dB, the typical uniformity was 0.67dB, and the insert-loss change before and after device-aging was 0.1 dB. The results showed the splitters meet the Bellcore GR-1209 standards well. All of the data concluded the process-analysis system of glass-based ion-exchanged optical components, which has the guiding value to the technology from experiment to industry. And the results also provide an important reference to optical power splitter chips and the other related components.In summary, this paper started with the charge density flux model introduced by electro-thermal effect, which makes the process of electric-field-assisted ion-exchange more stable and diverser and increases the controllability and flexibility of the fabrication of the waveguides and components. Furthermore, basing on the guidance of the new model, we improved the electric-field-assisted process and put forward the effective solutions for the bottleneck of the process. Finally, we fabricated the low loss single-mode waveguides and high-performance optical power splitters. Basing on these results, a complete process-analysis system for glass-based optical components is constructed, which opens up the road to the independent R&D of glass-based integrated optical chips in our country.