Bandwidth-Tunable Optical Amplifier with Narrowband Filtering Function Enabled by Parity-Time Symmetry at Exceptional Points
Kunpeng Zhu,
Xiaoyan Zhou,
Yinxin Zhang,
Zhanhua Huang,
Lin Zhang
Affiliations
Kunpeng Zhu
State Key Laboratory of Precision Measuring Technology and Instruments, Key Laboratory of Opto-Electronic Information Technology of Ministry of Education, Tianjin Key Laboratory of Integrated Opto-Electronics Technologies and Devices, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
Xiaoyan Zhou
State Key Laboratory of Precision Measuring Technology and Instruments, Key Laboratory of Opto-Electronic Information Technology of Ministry of Education, Tianjin Key Laboratory of Integrated Opto-Electronics Technologies and Devices, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
Yinxin Zhang
State Key Laboratory of Precision Measuring Technology and Instruments, Key Laboratory of Opto-Electronic Information Technology of Ministry of Education, Tianjin Key Laboratory of Integrated Opto-Electronics Technologies and Devices, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
Zhanhua Huang
State Key Laboratory of Precision Measuring Technology and Instruments, Key Laboratory of Opto-Electronic Information Technology of Ministry of Education, Tianjin Key Laboratory of Integrated Opto-Electronics Technologies and Devices, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
Lin Zhang
State Key Laboratory of Precision Measuring Technology and Instruments, Key Laboratory of Opto-Electronic Information Technology of Ministry of Education, Tianjin Key Laboratory of Integrated Opto-Electronics Technologies and Devices, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China
Integrated optical amplifiers are the building blocks of on-chip photonic systems, and they are often accompanied by a narrowband filter to limit noise. In this sense, a bandwidth-tunable optical amplifier with narrowband filtering function is crucial for on-chip optical circuits and radio frequency systems. The intrinsic loss and coupling coefficients between resonator and waveguide inherently limit the bandwidth. The parity-time symmetric coupled microresonators operating at exceptional points enable near zero bandwidth. In this study, we propose a parity-time symmetric coupled microresonators system operating near EPs to achieve a bandwidth of 46.4 MHz, significantly narrower than bandwidth of 600.0 MHz and 743.2 MHz achieved by two all-pass resonators with identical gain/loss coefficients. This system also functions as an optical bandwidth-tunable filter. The bandwidth tuning ranges from 175.7 MHz to 7.8 MHz as gain coefficient adjusts from 0.2 dB/cm to 0.4 dB/cm. Our scheme presents a unique method to obtain narrow bandwidth from two broadband resonators and serves as an optical bandwidth-tunable filter, thereby paving a new avenue for exploring non-Hermitian light manipulation in all-optical integrated devices.
