Measurement and application of optical nonlinearity in Ta2O5 waveguide

• Main Authors: Wen-Chun Chi, 齊文駿
• Other Authors: Chao-Kuei Lee
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/13569901710167249317

碩士 === 國立中山大學 === 光電工程學系研究所 === 104 === Nonlinear waveguide applications have been widely investigated in recent years. The nonlinear optical materials with high Kerr nonlinearity can be utilized to demonstrate supercontinuum generation as well as all-optical Kerr switch. In our work, we utilize Ta2O5 as the core layer of the waveguide to realize nonlinear waveguide applications. Due to the ultralow linear and nonlinear absorption loss of Ta2O5 from UV to infrared regions, the Ta2O5 is suitable for developing broadband and efficient nonlinear waveguides. The first part of my work is to demonstrate the SPM in the submicron Ta2O5 channel waveguide. By injecting fs pulse laser into Ta2O5 channel waveguide, the linewidth of Ti:sapphire laser is increased from 9 nm to 43 nm when the peak power is increased from 0 to 44W. The nonlinear refractive index of Ta2O5 at ~800nm is estimated to be 1.28×10-14 cm2/W. Furthermore, even the peak intensity is increased up to 29.38 GW/cm2, there is no nonlinear absorption effect in the Ta2O5 waveguide. In the second part of my work, we have realized the ultrafast all-optical modulation at communication region by using the Ta2O5 micro-ring resonator. By injecting a pulse laser into the ring resonator at resonance, the transmission spectrum of Ta2O5 micro-ring resonator can be modified due to the Kerr effect. That is, we can control the transmittance of the ring resonator around the resonance dip. Based on a pump-probe system, the CW-probe can be modulated by the pump pulse laser. The 0.045 nm wavelength shift of transmission spectrum in Ta2O5 ring cavity can be achieved by injecting the pulse laser with peak intensity of 0.12 GW/cm2. The nonlinear refractive index of Ta2O5 is calculated to be 3.4×〖10〗^(-14)cm2/W at ~1550nm, which is at least three times larger than Si3N4. Our results show that the Ta2O5 indeed has great potentials in developing the nonlinear waveguide applications.