Tailoring Of Silicon Nitride Waveguide Dispersion And Fabrication Of Low Thermal Sensitivity Interleaver

The generation and development of silicon photonics provides new approach to break the limilation of the moore law in silicon microelectronics.The applications of silicon in microelectronics are well-known.With the promotion of the mature microelectronic process technology and the ever-improving semiconductor material growth technology,the applications of silicon in photonics have shown unprecedented advantages and potential.Silicon nitride?SiN?,as another important photonics material,has its unique advantages in the field of biosensing applications at visble wavelengths,nonlinear optical applications at communication wavelengths and design of low thermal sensitivity devices.In this thesis,the deposition process of SiN films by the method of plasma enhanced chemical vapor deposition?PECVD?is investigated.A SiN-based waveguide with ultra-flat and low dispersion over an ultra-wide bandwidth is designed.A low thermal sensitivity SiN interleaver is designed and fabricated.The main contents are as follows:?1?The effects of several reaction conditions on the deposition rate,stress,surface roughness and refraction index of SiN films are investigated systematically,which include precursors?SiH₄ and NH₃?flow,chamber pressure and high/low frequency alternating growth time.?2?A SiN-based waveguide with ultra-flat and low dispersion over an ultra-wide bandwidth is designed.The dependence of the effective area and nonlinear coefficient on wavelength are calculated.The phase-matching condition of the degenerate four-wave mixing?FWM?is studied.?3?A SiN low thermal sensitivity interleaver is designed and fabricated,which is based on an asymmetric MZI with a microring resonator coupled to the short arm of the MZI.In the temperature range from 25°C to 70°C,the thermal sensitivity of the PMMA cladded device is reduced to within±7 pm/?C,and the maximized wavelength shift is 0.125 nm.