[20a-E205-1~12] 3.8 Optical measurement, instrumentation, and sensor

[20a-E205-12] Study on nonlinear processes in a waveguide device for ultrabroadband comb generation using optical frequency metrology

〇Kazumichi Yoshii^1,2, Junia Nomura^1,2, Kaho Taguchi¹, Yusuke Hisai^1,2, Feng-Lei Hong^1,2 (1.Dep. Phys. YNU, 2.JST, ERATO MINOSHIMA IOS)

Keywords:nonlinear optics, waveguide type device, metrology

Nonlinear devices based on waveguides are essential for highly efficient nonlinear optical conversion. However, the nonlinearity associated with the optical conversion in such devices is not self-evident. We introduce a new method using optical frequency metrology to reveal the nonlinearity inside a waveguide, and determined that the spectral broadening in a periodically poled lithium niobate waveguide is due to the quadratic nonlinearity. We also demonstrated an absolute frequency measurement using the generated ultra-broadband comb as an example of the practical application. This study will contribute to the design of chip-scale and fully-integrated devices for efficient nonlinear optical conversion.