High-frequency characterization of high-speed modulators and photodetectors in a link with low-speed photonic sampling

• 来源期刊: 半导体学报（英文版）
• 年，卷（期）: 2021,（4）
• 所属期刊栏目: ARTICLES
• 页码范围: 113-119
• 页数: 7页
• 语种: 英文
• DOI: 10.1088/1674-4926/42/4/042303

摘要

We propose a low-speed photonic sampling for independent high-frequency characterization of a Mach-Zehnder modulator(MZM)and a photodetector(PD)in an optical link.A low-speed mode-locked laser diode(MLLD)provides an ultra-wideband optical stimulus with scalable frequency range,working as the photonic sampling source of the link.The uneven spec-trum lines of the MLLD are firstly characterized with symmetric modulation within the interesting frequency range.Then,the electro-optic modulated signals are down-converted to the first Nyquist frequency range,yielding the self-referenced extrac-tion of modulation depth and half-wave voltage of the MZM without correcting the responsivity fluctuation of the PD in the link.Finally,the frequency responsivity of the PD is self-referenced measured under null modulation of the MZM.As frequency responses of the MZM and the PD can be independently obtained,our method allows self-referenced high-frequency measure-ment for a high-speed optical link.In the proof-of-concept experiment,a 96.9 MS/s MLLD is used for measuring a MZM and a PD within the frequency range up to 50 GHz.The consistency between our method and the conventional method verifies that the ultra-wideband and self-referenced high-frequency characterization of high-speed MZMs and PDs.