A Parabolic Waveform Generator Based on the Chirp Characteristics of a Directly Modulated Laser

• Published in: Photonics
• Main Authors: Na Chen, Yang Jiang, Xiaohong Lan, Yuejiao Zi, Jing Xu, Jiahui Li, Qiong Zhang, Jinjian Feng
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2023
• Subjects: DML; linear chirp; parabolic pulses; Applied optics. Photonics; TA1501-1820
• Online Access: https://doi.org/10.3390/photonics11010004; https://doaj.org/article/8358280f51e44cdc967f8cc2107becd6

Due to carrier dynamics, the modulated light field from a directly modulated laser (DML) has an intensity envelope with a certain frequency chirp. When the chirp is linearly mapped into intensity by a frequency discriminator such as an optical filter with a linear edge, the optical field presents a new signal determined by the multiplication operation between the envelope function and the chirp function. Under a triangular drive signal, this process can contribute dark, bright and frequency-doubled bright parabolic waveforms by properly adjusting the filter window. This method is verified by both a theoretical analysis and experimental demonstrations. It not only provides a low-cost and simple scheme to generate parabola signals, but also a new method for arbitrary waveform generation.