Thermo-optic tunable grating structure for coupler and radiator applications in silicon

• Main Authors: Kim, Seong-Hwan, Kim, Jong-Hun, Yeo, Sanggu, Kang, Geumbong, Kim, Jeongyoon, Yoo, Dongeun, Lee, Harin, Lee, Dae-Seong, Park, Hyo-Hoon
• Format: Conference Proceeding
• Language: English
• Published: SPIE 01.01.2017
• ISBN: 1510606599; 9781510606593
• ISSN: 0277-786X
• DOI: 10.1117/12.2252161

We propose tunable grating structures implemented by the change of the effective refractive index based on thermo-optic effect in silicon. For resistive heating, p-i-n or pn junction was formed in the grating region and surrounding region was thermally isolated. Fabricated tunable gratings were characterized by fiber-to-fiber measurement and Fourier-imaging system with a variation of the bias voltage applied to the heater. From a p-i-n type structure showing the best data, we achieved a wide tuning of the central wavelength in a range of 40 nm with an efficiency of 0.41 nm/mW. When this tunable grating structure is applied in the radiator of the optical phased array, the radiation angle was actively manipulated in a range of 2.7° in the longitudinal direction.