The Study Of The Carrier Injection Total Internal Reflection Optical Waveguide Switch Based On Silicon

Optical switch is the key component in optical switching system. A lot of schemes have been proposed in the past. Total-internal-reflection(TIR) optical switch has raised universal interest because it has many advantages such as the digital response to the driving signal, the nonsensitivity to wavelength and polarization and the relatively short length. Meanwhile, CMOS technology has been widely used in micro-electronic industry. If integrated optical device can be fabricated by CMOS technology, it will certainly fasten the development of the industrialization of the integrated optics.In this thesis, we aim to fabricate a SOI based small cross-section total-internal-reflection optical switch by industrial CMOS technology. In the production process, we found that many problems existed if we fabricate the small cross-section TIR optical switch by the tradition production scheme of an large cross-section one, mainly the serious impact of the metal electrode on the static properties and the thermo-optical effect on the dynamic performance. We analyze this point and propose an improved scheme.Based on this, this thesis gives a quantitative analysis of the impact of the metal electrode on the static properties and the thermo-optic effect on the dynamic performance of the switch. Result shows that due to the presence of the complex refraction index of the metal electrodes, there exists an inherent "static mirror" even when no voltage is applied, which debases the static properties. If we increase the intersection angle in order to have an acceptable static property, we will have to increase the injection current which will definitely degrade the switch property because of the thermo-optical effect. These phenomena are not serious in an large cross-section TIR optical switch, but for the small cross-section ones(thinner than 2.5μm), they become significant and even destroy the switch thoroughly.In order to diminish the impact of the above-mention two phenomena, we proposed a novel design of TIR optical switch. The device uses a deep etching with a shallow etching to shield the "static mirror" effect. This design can make electrodes restriction generous, so we can widen the electrode in order to achieve better heat dissipation to reduce the thermo-optical effect.