Research On Silicon-Based Optical Waveguide Microring Resonator And Traveling Wave-Like FP Resonator Devices And Their Applications

On-chip optical interconnect technology is widely used in information transmission and signal processing,through its strong anti-interference capability,low latency,low loss and large bandwidth.Microring resonators(MRRs)and traveling wave-like Fabry-Pérot cavities(TW-like FP cavity)can improve the performance of optical communication systems effectively.Due to the compact size,low power consumption and great flexibility,they are applied into many fields of silicon photonics.In this thesis,we theoretically analyze and experimentally study MRRs-based filters with ultra-high quality factor(Q factor)and MRRs-based thermo-optical devices,as well as the TW-like FP cavity-based optical filters and thermo-optical deveices.The main researches can be summarized as follows:(1)Ultra-high Q optical filters based on MRRs are proposed and implemented.By the processes of reflow and thermal oxidation,the waveguide transmission loss of MRRs can be reduced and Q factor can be improved.In this thesis,the effects of each condition are presented in terms of the multimode waveguide width and gap spacing between bus waveguides and MRRs,as well as in terms of the reflow and thermal oxidation processes,respectively.The fabricated ultra-high Q factor optical filter based on MRRs achieves Q factor exceeding 1×10~6,when the widths of bus waveguide and MRRs are 1.5μm,realizeing an low waveguide loss of about 0.2 d B/cm.(2)Thermo-optical devices based on MRRs are proposed and implemented.All-pass MRRs and coupled MRRs are fabricated by electron beam exposure and dry etching processes,respectively.Firstly,a single layer of graphene is laid on all-pass MRRs using etching and exposure processes,realizing the patterning of graphene on a silicon waveguide.The photo-induced thermo-optical refraction switching achieves the performance of low power consumption,easy integration and a fast time response of several hundred nanoseconds.In addition,metals are grown on the coupled MRRs.The thermo-optic effect is used to achieve wide-range controllable Q factor in directly coupled MRRs.The fabricated devices switch the system between the low-Q state and the high-Q state.(3)Optical filters based on TW-like FP cavities are proposed and implemented.Mode reflection and conversion in TW-like FP cavity are the basis.In this thesis,the theoretical model of Lorentzian resonance and Fano resonance based on TW-like FP cavities is proposed.By theoretical design,the fabricated optical filters achieve Lorentzian and Fano resonances,respectively,where the optical device with Fano resonance has an extinction ratio of 50 d B and a slope rate of more than 73 d B/nm at the drop port.In addition,the second-order flat-top filter is achieved by two identical TW-like FP cavities.The fabricated TW-like FP cavity with compact size and the same output direction for the through and drop ports is a promising resonator in the field of silicon photonics.(4)Thermo-optical devices based on TW-like FP cavities are proposed and implemented.The thermo-optical switch with low loss,large bandwidth and high tuning efficiency can be realized based on a TW-like FP cavity.In this thesis,the thermo-optical switch achieves a tuning efficiency of 0.274 nm/m W,which is consistent with the finite element simulation.Through the small mode volume of the TW-like FP cavity,the device achieves a tuning efficiency of 2.6 nm/m W.In addition,a four-channel reconfigurable add-drop multiplexer is fabricated by cascading TW-like FP cavities.The device could transfer signals to anyone channel at the drop port.Finally,the device achieves the uniform channel spacings of 400 GHz and 200 GHz,respectively.In this thesis,a series of theoretical and experimental studies have been carried out based on MRRs and TW-like FP cavities.The devices exhibiting high performance based on MRRs and TW-like FP cavities are expected to be widely applied in integrated photonic devices.