High performance thin-film lithium niobate modulator on a silicon substrate using periodic capacitively loaded traveling-wave electrode
Gengxin Chen,
Kaixuan Chen,
Ranfeng Gan,
Ziliang Ruan,
Zong Wang,
Pucheng Huang,
Chao Lu,
Alan Pak Tao Lau,
Daoxin Dai,
Changjian Guo,
Liu Liu
Affiliations
Gengxin Chen
State Key Laboratory for Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, International Research Center for Advanced Photonics, East Building No. 5, Zijingang Campus, Zhejiang University, Hangzhou 310058, China
Kaixuan Chen
Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, Sci. Bldg. No. 5, South China Normal University, Higher-Education Mega-Center, Guangzhou 510006, China
Ranfeng Gan
Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, Sci. Bldg. No. 5, South China Normal University, Higher-Education Mega-Center, Guangzhou 510006, China
Ziliang Ruan
State Key Laboratory for Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, International Research Center for Advanced Photonics, East Building No. 5, Zijingang Campus, Zhejiang University, Hangzhou 310058, China
Zong Wang
Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, Sci. Bldg. No. 5, South China Normal University, Higher-Education Mega-Center, Guangzhou 510006, China
Pucheng Huang
Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, Sci. Bldg. No. 5, South China Normal University, Higher-Education Mega-Center, Guangzhou 510006, China
Chao Lu
Photonics Research Center, Department of Electronic and Information Engineering, The Hong Kong Polytechnic University, Hong Kong, China
Alan Pak Tao Lau
Photonics Research Center, Department of Electrical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
Daoxin Dai
State Key Laboratory for Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, International Research Center for Advanced Photonics, East Building No. 5, Zijingang Campus, Zhejiang University, Hangzhou 310058, China
Changjian Guo
Guangdong Provincial Key Laboratory of Optical Information Materials and Technology, South China Academy of Advanced Optoelectronics, Sci. Bldg. No. 5, South China Normal University, Higher-Education Mega-Center, Guangzhou 510006, China
Liu Liu
State Key Laboratory for Modern Optical Instrumentation, Centre for Optical and Electromagnetic Research, International Research Center for Advanced Photonics, East Building No. 5, Zijingang Campus, Zhejiang University, Hangzhou 310058, China
Thin-film lithium niobate (TFLN) based traveling-wave modulators maintain simultaneously excellent performances, including large modulation bandwidth, high extinction ratio, low optical loss, and high modulation efficiency. Nevertheless, there still exists a balance between the driving voltage and modulation bandwidth. Here, we demonstrate an ultra-large bandwidth electro-optic modulator without compromising the driving voltage based on the TFLN platform on a silicon substrate, using a periodic capacitively loaded traveling-wave electrode. In order to compensate the slow-wave effect, an undercut etching technique for the silicon substrate is introduced to decrease the microwave refractive index. Our demonstrated devices represent both low optical and low microwave losses, which leads to a negligible optical insertion loss of 0.2 dB and a large electro-optic bandwidth with a roll-off of 1.4 dB at 67 GHz for a 10 mm-long device. A low half-wave voltage of 2.2 V is also achieved. Data rates up to 112 Gb s−1 with PAM-4 modulation are demonstrated. The compatibility of the proposed modulator to silicon photonics facilitates its integration with matured silicon photonic components using, e.g., hybrid integration technologies.
