| dc.description.abstract | This thesis focuses on a derivative structure of silicon photonic devices, specifically the microring resonator interferometer, which is a strong contender for future applications in AI and on-chip interconnect technologies due to its high bandwidth and low loss advantages, as well as its high integration with CMOS process technology. The emphasis of this paper is on the enhancement of the extinction ratio( ER) caused by the structure. Although microring resonators can achieve a very deep extinction ratio in simulations, the high extinction ratio of the transmission spectrum cannot be witnessed in actual processes due to the limited coupling strength of the components, which is why we chose this structure.
Initially, the Finite-Difference Time-Domain (FDTD) method is used for simulating small-scale structures to confirm their transmission characteristics, followed by numerical simulations for larger-scale structures. We use two simulation tools to model the transmission field patterns of large-scale structures, exploring the impact of different structure lengths and coupling factors on the extinction ratio. We also simulate the changes in the extinction ratio of the final transmission field pattern under different refractive indices. Modulators can be used to switch and modulate the extinction ratio of specific resonant peaks. This structure and its modulators can further enhance the quality of long-distance signal transmission in optical communications on the same wafer, as well as the detection precision of optical detectors and sensors.
For the component process, this paper chooses silicon nitride as the waveguide material and uses an i-line Stepper photolithography machine for the optical lithography process. After process optimization, high-quality factor samples are realized, and the feasibility of mass production is verified through full-wafer processing. For the measurement part, we use the 1550 nm optical communication band to analyze the transmission spectrum, verifying the extinction characteristics predicted in our simulations. Finally, we study how to improve the quality of the ring cavity, verifying that some fine microstructures can increase the quality factor by up to 50%. Through the action of the modulator, we achieved an extinction ratio improvement of 16 dB compared to the unmodulated structure, reaching a total of 35 dB. We also witnessed in simulations an 80 dB extinction component of 4 cascaded structures. The characteristics of this component can enable more applications in the fields of communication and sensing.
Using the i-line Stepper photolithography machine for the lithography process allows us to achieve mass production at a lower cost compared to current DUV and EUV deep ultraviolet scanning lithography machines. It also produces high-quality factor samples. This gives us an alternative to the low-cost contact lithography machines and the high time-cost scanning electron beam direct writing systems. | en_US |