A waveguide mode modulator based on femtosecond laser direct writing in KTN crystals

Results in Physics

Feng Chen¹  Yicun Yao²  Hongliang Liu³  Bin Zhang⁴  Yingying Ren⁵  Pengfei Wu⁶  Quanxin Yang⁷  Shan He⁷ 

[1] Corresponding authors at: Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China (H. Liu).;School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China;Shandong Provincial Key Laboratory of Optics and Photonic Device, School of Physics and Electronics, Shandong Normal University, Jinan 250358, China;School of Physics, State Key Laboratory of Crystal Materials, Shandong University, Jinan 250100, China;;Shandong Provincial Engineering and Technical Center of Light Manipulations &Tianjin Key Laboratory of Micro-scale Optical Information Science and Technology, Tianjin 300350, China;Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology, Insititute of Modern Optics, Nankai University, Tianjin 300350, China;

关键词: Optical waveguides;    Electrooptic devices;    Femtosecond laser direct writing;    Integrated optics device;   

DOI  :  

来源: DOAJ

【 摘 要 】

We report a novel mode modulator based on a KTN crystal waveguide produced by femtosecond laser (fs-laser) writing. The KTN waveguide is a typical dual-line structure that depends on the decrease of refractive index at the focus area. The propagation loss of the waveguide along the TE polarization is as low as ~0.9 dB/cm at 632.8 nm. The investigation of confocal micro-Raman spectra reveals that the microstructure of the waveguide region has no obvious change during the femtosecond laser direct writing (FsLDW) procedure. Under the applied direct current (DC) electric field, the waveguide modes in the guiding structure can be modulated, resulting in mode conversion from TE00 to TE02. Both the experimental results and the theoretical simulation indicate that the mode modulation phenomenon originates from the space-charge-field induced refractive-index increment between the waveguide core and the bulk substrate. The simplicity and remarkable performance of the demonstrated device paves the way for integrating low-cost and high-efficient electric-optical modulator on photonics circuits.

【 授权许可】

Unknown