Analysis Of Silicon-based Longwave Infrared Waveguided Components

The research of integrated optics devices is triggered by tremendous growth in the development optical communication technology as well as the giant needs of high speed internet access from the very beginning of 21st century. Moreover, the integrated silicon photonic devices are also attracting great interest for the potential applications in sensor, medicine, military as well as energy, far beyond traditional optical communication since more investigating in this territory. Currently, the wavelength of integrated optic components, however, is in the near-infrared waveband, mostly in 1.55μm. The middle and long wave infrared, located between the near infrared and the terahertz (THz) spectral regions, nevertheless, are own many interesting applications as well, especially in sensor and military use. Thus it is reasonable to extend the research of integrated optics to the mid- and long-wave infrared region.The waveguided components based on silicon platform are absolutely the main stream of opto-elecontronic integrated circuits (OEIC), since it combines the creativity of lab in universities and institutes as well as the state-of-the art CMOS technology of the industry. It is also much faster to commercialize the products than ever before. Lots of research groups are focused on it with an increasingly nμmber of reported novel structures and effective devices.Based on the issue mentioned above, the thesis is intended to explore the principles of designing LWIR waveguided components, straight waveguides and MMI on wafer or SOI are fabricated with the CMOS-compatible technique to verify those rules. Generally speaking, the innovative work of this thesis can be summarized as follow:1. Analysis the scaled-up principle which is meaningful to design devices based on slot waveguides in LWIR condition. Slot waveguides play an important role in constructing sensors. To illustrate the way of using scaled-up principle, we take the wavelength of 10.6μm as the example. The larger slot width and lower technique requirement can be achieved in the condition of longer wavelength infrared. 2. Build the set-up with the laser source in the wavelength of 10.6μm for the measuring the loss of waveguides. This set-up is mainly based on the CO2 laser, chopper, attenuator, focusing lens, objective table, detector and lock-in amplifier.3. Design two kinds of structures of LWIR waveguides simulating by BPM and FE method, explore the experimental technique and acquire the propagation loss:13±1dB/cm@10.6μm for the large cross section waveguide and 10±0.6dB/cm@10.6μm for the undercut waveguide, respectively.