DOI: 10.3390/photonics11010004 ISSN: 2304-6732

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

Na Chen, Yang Jiang, Xiaohong Lan, Yuejiao Zi, Jing Xu, Jiahui Li, Qiong Zhang, Jinjian Feng
  • Radiology, Nuclear Medicine and imaging
  • Instrumentation
  • Atomic and Molecular Physics, and Optics

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.

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