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Linewidth Narrowing of External‐Cavity Semiconductor Lasers Under Direct Frequency Modulation
Author(s) -
Rongqing Hui,
Yizun Wu
Publication year - 1989
Publication title -
microwave and optical technology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.304
H-Index - 76
eISSN - 1098-2760
pISSN - 0895-2477
DOI - 10.1002/mop.4650020609
Subject(s) - laser linewidth , semiconductor laser theory , modulation (music) , materials science , laser , optics , frequency modulation , optoelectronics , modulation index , phase modulation , semiconductor , phase (matter) , physics , phase noise , radio frequency , pulse width modulation , telecommunications , power (physics) , acoustics , quantum mechanics , computer science
Abstract A simple formula of linewidth narrowing ratio of external cavity semiconductor lasers under direct frequency modulation was given. The theoretical result gives an explanation to the previous experimental observation. The decrease of the linewidth narrowing ratio and the change of the “in‐phase” condition depend on the modulation index, signal frequency, and external‐cavity length, as well as the optical feedback efficiency. A short external cavity with strong optical feedback can minimize the influence of the direct frequency modulation.