Study Of Multimode Interference Integrated Optical Devices On The Glass Substrate

In view of the tread of the informational society, the developing of FTTP/FTTH draw the whole optical communication market to a new stage. Integrated optical devices are becoming more and more important due to the fast developing optical network. In order to fulfill the requirements of the developing optical communication system, the research and development of the optical devices, which are the key components of the fiber communication system and optical network, have been highly requested.Multimode interference (MMI) devices, which are based on the self-imaging effect (SIE), have many merits, such as compact size, low insertion loss, ease of production and good fabrication tolerances. The MMI devices are of great prospect in integrated optics. In recent years, there has been a growing interest in MMI-based devices. Several MMI devices have been reported, such as optical splitters or couplers, switches, mode splitter and mode converters. At the same time, they are the key components as many optical function modules, such as wavelength-selective switches, ring lasers, interference transverse filters and multi-wavelength light sources.In this thesis, the current research situation of the important integrated optical devices in the optical network, such as optical switches. Then we summarized the research works of MMI devices and the fabrication of glass based integrated optical devices. Under the research condition of our laboratory, we have made studies on glass based MMI splitters and couplers and polymer thermo-optical switches based on multimode interference structure.In the earliest stage, we make studies of multimode interference devices under the condition of the step index profile. However, there are some devices with graded-index waveguides, which make an important role in integrated optics. Glass has been the most popular material to make passive components and lithium niobate is most commercialized material at present. After making analysis and simulation of SIE in graded-index waveguides, we design the MMI NxN optical coupler and 1 ×N optical splitter on the glass substrate. Then we fabricate the devices using ion-exchange process. The measurement show that the devices have been realized the excellent performance of the MMI devices with the graded-index profile.In addition, we study the polymer thermo-optical devices with MMI structure. The theoretical analysis shows the good performance of such devices. Then we measure the fabricated the polymer thermo-optical VOA. The results show that the devices have been realized the good performance as we designed.At present MMI devices with different structures on different substrates are drawing more and more attention. We believe that there will be more and more theoretical and practical results on MMI devices in the near future.