A novel method to suppress nonlinear distortion of directly modulated laser diode using dual parallel modulation scheme has been proposed. This scheme exploits that the frequency chirping influences the phase of RF signals. Two properly controlled undesired intermodulation signals with out-of-phase difference are cancelled via coherent RF recombination at the photodetector. The validity of this scheme was confirmed through experiments. From experiments, the 20-dB reduction of the third-order intermodulation distortion was achieved and the tunability of suppression region was observed.
Bibliographical noteFunding Information:
Manuscript received August 23, 2001; revised February 20, 2002. This work was supported in part by the University Research Program (2001-059-3) and by Ministry of Information and Communication in South Korea. The authors are with the Department of Electrical and Electronic Engineering, Yonsei University, Shinchon-Dong, 120-749 Seoul, Korea (e-mail: firstname.lastname@example.org). Publisher Item Identifier S 1041-1135(02)04613-X.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering