Abstract
The high-frequency modulation of semiconductor laser’s pump current is used in several important applications, such as high-speed data telecommunications[1], direct-modulation optoelectronic oscillators[2], optical sampling with gain-switched regimes and so forth. The linewidth enhancement factor (LEF) is the quantity that describes the coupling of phase fluctuations to intensity fluctuations and has important consequences such as laser linewidth broadening and pulse chirping. A good knowledge of the LEF is essential to predict the behavior of a modulated laser. The measurement of the LEF is tricky and many methods have been proposed, based on optical injection/feedback, on small/large signal modulation, or on spectral measurements[3]. Here we propose a novel method[4] based on the complete optical field reconstruction technique[5]. This method is of rather simple im-plementation and requires common opto-electronic lab instruments, i.e. a Mach-Zehnder modulator (MZM), RF synthesizers, a RF phase shifter, a direct-modulation laser and an optical spectrum analyzer (OSA), see Fig. 1a. The technique consists in modulating the source and measuring the optical spectrum for various RF delays τ, and allows retrieving iteratively the spectral phase.
© 2023 IEEE
PDF ArticleMore Like This
Kenji Wada, Masahiro Kitamura, Yuichi Akage, and Yoshio Cho
CWH34 Conference on Lasers and Electro-Optics (CLEO:S&I) 1994
Zhuqiu Chen, Yuxi Ruan, Bairun Nie, Yanguang Yu, Qinghua Guo, Jiangtao Xi, and Jun Tong
JM5A.53 Advanced Solid State Lasers (ASSL) 2019
Guido Giuliani, Silvano Donati, Asier Villafranca, Javier Lasobras, Ignacio Garces, Marek Chacinski, Richard Schatz, Christos Kouloumentas, Dimitrios Klonidis, Ioannis Tomkos, Pascal Landais, Raul Escorihuela, Judy Rorison, Jose Pozo, Andrea Fiore, Pablo Moreno, Marco Rossetti, Wolfgang Elsässer, Jens Von Staden, Guillaume Huyet, Mika Saarinen, Markus Pessa, Pirjo Leinonen, Ville Vilokkinen, Marc Sciamanna, Jan Danckaert, Krassimir Panajotov, Thomas Fordell, Asa Lindberg, Jean-Francois Hayau, et al.
CB9_2 The European Conference on Lasers and Electro-Optics (CLEO/Europe) 2007