Design and modeling of highly tunable filters based on the linear electro-optic effect in strained silicon waveguides

作者：Mehrfar Farzaneh^*; Soofi Hadi; Pourziad Ali

来源：Optical Engineering, 2017, 56(8): 086106.

DOI：10.1117/1.OE.56.8.086106

• contradirectional couplers
• linear electro-optic effect
• Pockels effect
• silicon photonics
• tunable filter

Design and modeling of wavelength tunable filters based on the linear electro-optic (Pockels) effect in strained silicon waveguides is presented. The structure is based on the silicon grating-assisted contradirectional couplers. The basic idea is to utilize a silicon nitride (Si3N4) layer on top of the silicon waveguides to induce a relatively large Pockels effect in the waveguides by breaking the centrosymmetry of the Si crystal due to the surface strain. Wavelength tuning is obtained by applying DC voltages to the device contacts on top of the Si3N4 layer. Based on the presented structure, a wavelength tunable filter at the C-band communication window is designed and its characteristics were investigated by full-vectorial finite-element and finite-difference timedomain methods for electrostatic and optical responses. A 3.5-nm wavelength shift for an applied voltage of 1 V and a 7.5-nm shift for an applied voltage of 5 V are obtained with negligible loss. The presented device is superior to the previously reported structures in terms of tunability and loss.

• 出版日期2017-8