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The Study Of Optical Signal Processing Technology Based On Photon-Liquid Crystal And Hybrid Plasmonic Waveguides

Posted on:2016-10-17Degree:DoctorType:Dissertation
Country:ChinaCandidate:J DaiFull Text:PDF
GTID:1108330467498545Subject:Optical Engineering
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With the development and process of society, optical fiber communication technology has been increasingly developed and attention. In order to maximize the transmission capacity and meet customers’ different bandwidth demand r to achieve the minimum cost, the fiber optic communication systems are constantly moving to the direction of large capacity, ultra-fast, ultra-wideband, ultra-long haul, low-cost. Due to that optical devices are key parts of the optical signal processing, thus they play an impotart role in the optical communication network system. Thus optical devices with versatility and diversity occupy an important position in optical signal proceesingIn this thesis, we have studied the relevant technologies of the optical signal processing based on Photon-Liquid Crystal Waveguide and Hybrid Plasmonic Waveguide. For Photon-LC waveguide, we have analyzed the mechanism of the beam control and wavelength tunable characteristics in the relevant waveguide devices; for Hybrid Plasmnic Waveguide, we have analyzed all-optical wavelength conversion and all-optical logic operations in the relevant waveguide devices. The main research achievements are as following:A novel optical phased array based on Liquid crystal is studied, and its structure scheme feature is a planar wavegude with liquid crystal cladding. Propagation, output diffraction characteristics and other peformances of liquid crystal-optical phased array are all studied and analyzed according to Frank-Oseen continuum elastic theory and grating diffraction theory. The research results show that the electrical control phase delay of the device is quantitatively analyzed to obtain larger optical path difference, and the validity of light beam control is also demonstrated; this novel strcture could improve the response time for an order of magnitude as well as wavelength dispertion of the device. These theoretical basis and technical design basis are favour of developing this novel liquid crystal-optical phased array in the future.A tunable microring resonator (MRR) based on photon-LC slot waveguides is proposed. This device consists of an SOI slot MRR, an upper cladding of LC and a specific electrode structure which connects control voltage. Two research schemes are listed: Firstly, we design a single-slot LC MRR, which offers a wide wavelength tuning range (-56.0run) and a large FSR(~28.0nm), and the operation voltage is only5V;Secondly, a double-slot LC MRR is designed for future study, it could achieve a relatively large dynamic wavelength tuning range of81.4nm and well fabrication tolerance. In addition, the tunable double-slot LC MRR could keep the wavelength tuning range over about60nm even if considering that key structure parameters and fabrication deviation.We study the third-order nonlinearity four wave mixing (FWM) of a symmetric hybrid plasmonic waveguide (SHPWG) configuration, which offers an extremely large nonlinear parameter γ>104m-1W-1and a very large effective propagation length Lp~1.5mm. In addition, a QPM technique is adopted to achieve a relatively long effective length of FWM nonlinear process by constructing a long SHPWG grating, and it results in highly efficient wavelength conversion bewttwen C-band (1530~1565nm) and mid-IR band (2118~2180nm). By using numerical simulations we have demonstrated that, for a pump wavelength of1800nm, an efficient and flat FWM conversion of~-17dB (or~-22dB) could be realized around a target signal wavelength of C-band (or mid-IR band), in a1000-μm-long grating with serious phase mismatch.A novel all-optical logic gate is demonstrated by means of polarization-dependent four-wave mixing (FWM) processes in a highly nonlinear silicon hybrid plasmonic waveguide (HPWG) microring resonator. We design an ultra-compact (radii=1μm) microring resonator (MRR) realized by using silicon HPWG with the ability of subwavelength-bending. By manipulating the polarization properties of the pump and signals, all optical NOT, NOR and NAND logical operations are obtained through FWM process. These compact all optical nanoplasmonic devices are stable, fabrication simplified, silicon on insulator (SOI) compatible, and exhibit potential in miniaturization and integration of all-optic circuits..
Keywords/Search Tags:Liquid crystal (LC), Surface Plasmon (SP), Optical Phased Array (OPA), Slot Structure, Microring Resonator (MRR), Four Wave Mixing (FWM), All-optical Wavelength Conversion, All-optical Logic Gate
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