Cascaded frequency conversion and EO effect can modulate the nonlinear process conveniently via an applied electric field. But there are two crucial issues in previous implementations. On one hand, the cascading process based on bulk media is inefficient in both frequency conversion and electric field per applying voltage. On the other hand, the operating wavelength of the cascaded SHG and EO polarization coupling is limited.

We propose a new scheme to address these issues by utilizing the cascading of SFG and EO polarization coupling. We succeeded to manipulate the intensity of SFG via EO polarization coupling by taking the advantage of the cascading process in a PPLNOI ridge waveguide. Both the driving voltage and input power is dramatically reduced due to enhancement on the integrated LNOI platform. As the conditions of SFG and EO polarization coupling are relatively independent, the current configuration is flexible and operational at a wide wavelength range. The scheme will find applications in integrated electro-optical modulator, nonlinear optical processing, etc.

Fig. | Concept of cascaded SFG and EO polarization coupling in the PPLNOI ridge waveguide

This research was published in “Dan Wang, Tingting Ding, Yuanlin Zheng, and Xianfeng Chen, Cascaded sum-frequency generation and electro-optic polarization coupling in the PPLNOI ridge waveguide, Optics Express, 27(11), 15283-15288 (2019).”