The Research Of Optical Silicon Waveguide And Nano-waveguide Based On Glass

The fast development of optical communication brings forward higher and higher requirements to integrated optics. The opto-electronic integration can highly drive costs down, optimize the devices' performance, and achieve complex functions. But at present all kinds of discrete optical waveguide devices are too large to be integrated. As the basic of the optical waveguide devices, the research of optical waveguide's miniaturization becomes very important. The nanometer-sized waveguide with high refractive index difference has become a focus in the research of planar optical waveguide devices. It is absolutely the necessary first step toward the photonic integration. We adopted the technology of silicon-glass bonding and selective etching to develop a kind of new waveguide material: silicon on glass. We also built the ridged waveguides, planar and rectangular waveguides on this material, among which the last two waveguides reached the extent of nanometer.This thesis starts with introducing the research progress of nanometer-sized waveguide and devices from waveguide materials and structures. Afterward it goes to the design of waveguide structure from the aspects of single mode, loss and coupling. Then it provides the analysis and discussion of the key technologies, such as the improvement of bonding quality, and the realization of etched-back. This thesis also explains the key techniques in the experiment, and in the end it expatiates the experiment results from roughness, loss, and thickness uniformity.From the measuring result, the obtained SOG martial can remain good quality of surface silicon. When the used SOI material is based on SIMOX technology, the root-mean-square surface roughness is about 3 nm, the silicon thickness uniformity is less than 5%, and the thickness of silicon film can be tens of nanometers to several microns. Meanwhile, it has many advantages, such as a thicker optical waveguide's bottom confining layer than SOI materials; better confinement to core area in nanometer-sized waveguides; and a high refractive index difference to makenanometer-sized optical waveguides.The minimum loss of ridged optical waveguide built on the SOG with a 5-micron silicon layer is 1.06dB/cm, and the minimum loss of ridged optical waveguide built on SOI with the same fabrication condition is 1.28 dB/cm. They are at the same order of magnitude. So it initially proved the feasibility of producing this kind of glass-substrate optical waveguide material. The loss of rectangle waveguide built on the SOG with a 500 nm top silicon layer is 1.2 dB/cm.Another strongpoint of this producing technological process is that before glass bonding with SOI, we can sputter metal electrodes on the glass or SOI, and then make the electrodes on the top silicon after the bonding and etching work, so that we can modulate the upper and lower structured electrodes on the optical waveguide and increase the modulation efficiency. So we at last based on this technology design the variable optical attenuator, 1 X 2, and 2X2 optical switches. Compared with traditional ones, the devices of this structure have smaller sizes: the variable optical attenuator has the length of only 7 mm, and the 2X2 switch's length is also only 1 cm.