In this talk, we propose gallium oxide as a new optical material platform for integrated photonic applications in the ultraviolet to visible (UV-visible) spectral. First, we report the characterizations on optical nonlinearities of beta-phase gallium oxide (β-Ga~2~O~3~), where both (010) β-Ga~2~O~3~ and (-201) β-Ga~2~O~3~ were examined for two-photon absorption coefficient, Kerr nonlinear refractive index, and their polarization dependence. The wavelength dependence of two-photon absorption coefficient and Kerr nonlinear refractive index were also estimated by a widely used analytical model. β-Ga~2~O~3~ exhibits a two photon absorption (TPA) coefficient of 1.2 cm/GW for (010) β-Ga~2~O~3~ and 0.6 cm/GW for (-201) β-Ga~2~O~3~. The Kerr nonlinear refractive index is −2.1×10^−15^ cm^2^/W for (010) β-Ga~2~O~3~ and −2.9×10^−15^ cm^2^/W for (-201) β-Ga~2~O~3~. In addition, β-Ga~2~O~3~ shows stronger in-plane nonlinear optical anisotropy on (-201) plane than on (010) plane. Second, we report the fabrication of low loss β-Ga~2~O~3 ~optical waveguides and the propagation loss analysis of the waveguides in the UV to near infrared (NIR) spectral region. The β-Ga~2~O~3 ~thin films were grown on sapphire substrates using metal organic chemical vapor deposition and were fabricated into various waveguide structures using nanofabrication processes. A low propagation loss of 3.7 dB/cm was obtained on the β-Ga~2~O~3~ at the wavelength of 810 nm, which is comparable to the state of the art. Combined with theoretical simulations, various loss mechanisms from two-photon absorption, sidewall scattering, top surface scattering, and bulk scattering were discussed for β-Ga~2~O~3~ waveguides, and their contributions to the total optical loss were estimated. These results indicate that β-β-Ga~2~O~3~ have the potential for ultra-low loss waveguides, ultra-stable resonators, and integrated photonics, especially in UV-visible wavelength spectral range.

 

 


Gallium Oxide as an Exciting New Optical Material for the Ultraviolet and Visible Integrated Photonics Applications

Division / Sponsors: 
Electronic & Photonic Packaging Division (EPPD)

Paper Proceedings: https://asmedigitalcollection.asme.org/InterPACK/InterPACK2020/volume/84041

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