| With the rapid development of modern information technology,there is an increasing demand for information processing systems with higher speed and smaller volume.Traditional electrical communication technology is gradually transforming into the optical communication technology with photon as the information carrier.With the ability of strong field confinement and the characteristic of breaking diffraction limit,surface plasmon polaritons(SPP)make the manipulation of light on nanoscale possible.Plasmonic interconnect circuits(PICs),in which SPP is utilized as information carrier,are expected to realize the fusion of electronics and photonics at the deep subwavelength scale,bringing a revolutionary breakthrough in photonic integration.As one of the core devices in PICs,the SPP detector operates as SPP signal readout device and optoelectronic information exchange interface.The performance of the SPP detector is therefore the key to the construction of ultra-high speed and high-bandwidth PICs.In this thesis,considering the low detection efficiency,complex preparation process and difficulty in integration in existing SPP detectors,the feasibility and working mechanism of SPP detection in periodic gratings which is compatible with CMOS technology and easy to integrate were studied.On this basis,a novel wavelength-polarization multiplexer was proposed to realize wavelength-polarization multiplexing function.In addition,the structural parameters of the SPP detector were optimized to improve the detection performance.This work provides theoretical and experimental basis for the realization of high-efficiency and high-speed SPP detector and the construction of PICs.The main research achievements of this thesis are as follows:(1)A SPP detector based on periodic grating structure was proposed.The relationship between the coupling efficiency and the polarization angle of the incident light was analyzed by numerical simulation,along with that between the absorption efficiency and the waveguide length.Further,the SPP detector was prepared by electron beam lithography(EBL)process.The influence of incident light power,polarization state and incident area on photocurrent was investigated in detail.The experimental results were in agreement with the simulation data,demonstrating the feasibility of detecting SPP in periodic gratings.(2)A wavelength-polarization multiplexer based on periodic gratings was designed and fabricated by combining wavelength multiplexing and polarization multiplexing technology.The output states of four detection channels in the multiplexer at 532 nm and 660 nm with different incident polarization states were analyzed by experiments and numerical simulations.The wavelength-and polarization-dependent routing and detection of SPP were realized,which provides a new idea for constructing high-bandwidth plasmonic interconnection.(3)A planar SPP detector composed of interdigital gratings and silicon substrate was optimized.The detection performance of the planar interdigitated grating-silicon substrate structure and the vertical SPP detector based on periodic gratings were comparatively studied.Owing to the efficient carrier collection capability,the planar interdigitated grating-silicon substrate structure exhibited excellent performance.Compared with the vertical SPP detector,the responsivity and speed of the planar detector were increased by 31 times and 3.8 times,reaching 193 m A /W and 91.5 ?s,respectively.(4)To solve the problem of low efficency in the existing SPP detectors,the interdigitated grating-silicon film-metal reflector was proposed.The effect of the bottom metal reflector on the detection efficiency of SPP was studied.The coupling between the SPP mode and the interdigitated grating wass effectively enhanced by the reflection of bottom metal reflector,thus improving the SPP detection efficiency.This work provides a feasible direction for the realization of high-efficiency SPP detector in the future. |
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