Bias Controller of Mach–Zehnder Modulator for Electro-Optic Analog-to-Digital Converter
Shuxin Shi,
Jun Yuan,
Qin Huang,
Chongyu Shi,
Xin Luo,
Shan Lu,
Pengfei Yuan,
Hua Yu,
Qiuqin Yue
Affiliations
Shuxin Shi
Key Laboratory for Optoelectronic Technology &Systems, Ministry of Education of China, Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology, Chongqing University, Chongqing 400044, China
Jun Yuan
Science and Technology on Analog Integrated Circuit Laboratory, Chongqing 401332, China
Qin Huang
Key Laboratory for Optoelectronic Technology &Systems, Ministry of Education of China, Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology, Chongqing University, Chongqing 400044, China
Chongyu Shi
Key Laboratory for Optoelectronic Technology &Systems, Ministry of Education of China, Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology, Chongqing University, Chongqing 400044, China
Xin Luo
Key Laboratory for Optoelectronic Technology &Systems, Ministry of Education of China, Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology, Chongqing University, Chongqing 400044, China
Shan Lu
Key Laboratory for Optoelectronic Technology &Systems, Ministry of Education of China, Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology, Chongqing University, Chongqing 400044, China
Pengfei Yuan
Key Laboratory for Optoelectronic Technology &Systems, Ministry of Education of China, Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology, Chongqing University, Chongqing 400044, China
Hua Yu
Key Laboratory for Optoelectronic Technology &Systems, Ministry of Education of China, Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology, Chongqing University, Chongqing 400044, China
Qiuqin Yue
Chongqing College of Electronic Engineering, Chongqing 401331, China
As one of the core devices for an electro-optic analog-to-digital converter (ADC), the Mach−Zehnder (MZ) modulator plays an important role, and the output stability of the MZ modulator has a decisive influence on the conversion accuracy of the ADC. This paper proposed a pilot tone-based method to stabilize the bias point of the modulator. This method could obtain the corresponding control voltage of the MZ modulator by adding a KHz-level dither tone to the bias end of the modulator and calculating the ratio of the first and second harmonic components. The experimental results showed that the output optical power of the modulator was stable at 3.2 dB when the bias point of the modulator was set at the orthogonal point. Moreover, the fluctuation range was not more than 0.15 dB, the first harmonic of the output signal was stable at 50.5 dB, and the fluctuation range was not more than 0.6 dB. The proposed bias controller based on the field programmable gate array (FPGA) and digital signal processing (DSP) can stabilize the modulator bias point at the orthogonal point and with a relatively high locking accuracy.
