Study Of Slot-based Optical Devices

Integrated optical devices plays an important role in the development of modern large-capacity and high-speed optical network,and in the fields of on-chip optical interconnection, photovoltaic,display, sensing,etc. It moves now to be more compact,integrated,and energy-saving.Silicon, as a material with large refractive index difference, low cost and being compatible with the mature micro-electronics platform, is getting more and more attention, and has already achieved lots of technological breakthroughs. However the active devices based on it are still underdeveloped for the limitation of the corresponding physical properties.In order to get use of the excellent passive characteristics of silicon and its compatibility with the micro-electronic devices, meanwhile overcoming the physical shortage of it,in recent years people are trying to hybrid integrate silicon with other materials to complement advantages.For example to integrate silicon devices with lasers and photodetectors made byⅢ-Ⅴsemiconductors,or to realize active characters on silicon platform by using slot structure which has a lower cost and is more simple. In this thesis,first the basic principle of the slot structure and its applications are summarized, and then a series of analyses and experimental attempts are proposed. The main innovation and contribution are:1.Based on the principle of Mach-Zehnder interference, a high-speed electro-optical silicon optical switch is proposed by filling electro-optical polymer inside the slot structure of the interference arms.The device length is only few hundreds micrometers,the modulation frequency can achieve 83GHz even by using the lumped electrodes,and the power consumption is only 37fJ/bit,much advanced than the carrier dispersion type devices studied till now.2.In order to overcome the drawbacks that the performance of the Y-branch digital optical switch is not very good and the device size is large, also by filling electro-optical polymer,a high-speed compact silicon digital optical switch with the slot structure is proposed. Then the performance improvement by introducing the multi-slot structure is discussed.3. Since it is hard to etch the slot through for the vertical slot structure, an improved electrode with reverse p-n junction is proposed. It can maintain electrical isolated for the unideally etched case, and even for the rib-type slot structure. The fabrication tolerance of it is large and it is easy to realize.4.Symmetric and asymmetric Mach-Zehnder type micro-fluidic sensor based on the slot structure is proposed, also by folded interference arms,the device length can be largely shortened, and the theoretical sensing sensitivity is high. We use the foundry of IMEC in Europe and SMIC in Shanghai for fabrication. The typical width is 0.18μm, which is advanced in domestic.5. Tried to fabricate horizontal slot structure filled with polymer in our laboratory. Some phasic achievements are gained, the difficulties and the possible methods for ameliorating are discussed.