The Theoretical Study On The EIT-like Effect In Photonic Crystal Coupled Resonators Systems

In the process of realizing the all-optical network, one of the big difficulties that have toface is how to realize the slow light and the optical buffers. Compared with the materialdispersion, achieving slow light through structure dispersion is easier. As a kind of artificialand periodical material, photonic crystal possesses many advantages. Good performance atroom temperature, easy to fabricate, unlimited to specific wavelengths etc., making it aperfect candidate to study slow light. In recent years, achieving slow light through photoniccrystal waveguide as well as the microcavities and waveguide coupled systems have becomethe focus of the research.In this thesis, we use the all-optical Electromagnetically Induced Transparency (EIT)like effect which is produced in silicon-based photonic crystal coupled resonators systems torealize slow light. We first make a study on the characteristics of a single cavity as well as itscoupling with the waveguide, which provide a basis for the research of optical EIT effect.Then we use the transfer matrix method to compute the transmission spectrum and theoptical delay curves of the EIT-like effects. Compared to the former method through solvingthe coupling mode equations, our method eliminates the complex solving processes. It is alsohelpful in our understanding of coupling process and the EIT-like effect. On this basis, weinvestigate the relationships between the optical EIT peak and related parameters-qualityfactors of the cavities, resonant wavelength detuning Δλ and the phase difference detuningΔΦ between the cavities. Furthermore, we proceed the simulations of both EIT-like systemscomposed of L3cavities as well as heterojuntion cavities and coupled waveguide through3D FDTD method. For the two heterojunction cavities and waveguide coupled system, wefind EIT-like effect at two different wavelengths, which is usually realized throughthree-cavity-cascading system. Due to the high Qint/Qcvalues of the modes therein, opticaldelays about an order of magnitude larger than previous report are realized for each opticalEIT peak.Our work paves the way for further experimental research of multi-wavelength opticalEIT effects and long optical delay devices. It also gives a new direction and support for newapplications such as optical switches, narrow band filters, and logic gates.