Research On The Nonlinear Optical Characters And Applications Of Slot Waveguides

With the high-speed development of human science and technology, the Internet connects everyone in the daily life, and the human gradually enter the information society. As a result, there has a higher requirement for the speed of information exchange, and large information capacity. However, optical communication network with its unique performance (including large capacity, high rate, low-loss and strong anti-interference capability), can satisfy people demand of communication capacity and information exchange. In the high speed large capacity optical communication, optical signal processing plays a important role, as the optical signal amplification, regeneration, high-speed optical pulse generation and shaping, wavelength conversion and multi-channel source etc. In recent years, people found that the photonic integrated devices can easily realize the above optical signal processing. The characteristics ahout photonic integrated devices of low power consumption, low cost, the small dimension of photonic integrated devices, energy concentration, are helpful to use the nonlinear effect to realize various functions.In this theis, we have studied dispersion tailoring and nonlinear control features of slot waveguide, and researched the nonlinear optical characters and relevant applications in slot waveguides. For the double-slot straight waveguide and double-slot microring waveguide with arsenic sulfide and silica, we have stuied and analyzed the broadband and transparant wavelength conversion, and flat optical frequency comb generation. For the single-slot straight waveguide with PTS and silicon, we have analyzed the features about octave-span coherent supercontinuum spectrum generation.The main research achievements are as follows:A novel broadband and transparent wavelength converter is proposed. The flat and low second-order dispersion of 0? -13 ps2/km in a double-slot waveguide is optimized for broadband wavelength conversion. Subsequently, a 3-dB conversion bandwidth about 1200 nm is presented by four-wave mixing based on the above structure in simulation. Attributed to the small phase-mismatch caused by low second- and fourth-order dispersion parameter in large waveband, the 3-dB conversion bandwidth is almost constant at about 1200 nm with the pump wavelength varying from 2200 nm to 2800 nm. The results indicate that this dispersion-flattened double-slot waveguide is not only an ideal device for broadband wavelength conversion, but also can realize the transparency of pump wavelength, which has potential applications in wavelength conversion.A slot waveguide with single horizontal PTS slots is proposed to achieve high nonlinearity coefficient and flat dispersion. The flat dispersion varying between 0-56 ps/ (nm km) is obtained over an 720 nm bandwidth. A broadband supercontinuum spectrum, spanning from 1.108 to 2.488 ?m in the -34dB level was generated in this waveguide pumped by a femtosecond pulse at 1.6 ?m, corresponding the nonlinearity coefficient is 4200/(W·m). Meanwhile, we study the coherence of the supercontinuum spectrum. The numerical simulations show that the broadband supercontinuum is fully coherent. This coherent spectrum may be utilized for spectroscopy, and frequency metrology. Results indicate that the waveguide has great potential in near- infrared nonlinear applications.A novel double-slot microring resonator is proposed to produce flat dispersion of 0-3.8 ps/(nm·km) over 1150 nm wavelength range. Moreover, the dispersion tailoring with different structural parameters of the proposed microring resonator is analyzed and simulated. The simulation results show that the dispersion fluctuation can be tailored by the height of the central and bottom AS2S3 layer, and the slope can be adjusted by the waveguide width and lower SiO2 slot thickness. Furthermore, by means of the Lugiato-Lefever equation, an ultra-flat and broad optical frequency comb with 7 dB bandwidth of 1155 nm (1855?3010 nm) is obtained based on such dispersion optimized resonator. The proposed double-slot microring resonator shows potential application in both telecommunication and mid-infrared research domain.