A1 Refereed original research article in a scientific journal
Linewidth measurement of external cavity lasers
Authors: Kuusela, Tom A.
Publisher: AIP Publishing
Publishing place: MELVILLE
Publication year: 2024
Journal: American Journal of Physics
Journal name in source: AMERICAN JOURNAL OF PHYSICS
Journal acronym: AM J PHYS
Volume: 92
Issue: 6
First page : 459
Last page: 465
Number of pages: 7
ISSN: 0002-9505
eISSN: 1943-2909
DOI: https://doi.org/10.1119/5.0207084
Web address : https://doi.org/10.1119/5.0207084
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/457044522
Narrowband laser sources are used in applications that require high-precision or stable optical frequency. Such applications include high-resolution spectroscopy, long-distance measurement, and coherent optical communication. The linewidth of a laser is a direct measure of the laser's stability; therefore, characterization of laser linewidth is essential. In practice, however, determining a laser's linewidth is not a trivial task and typically requires expensive equipment or a complex experimental arrangement. This paper presents a straightforward, low-cost method based on unbalanced interferometry, which allows us to determine the visibility of fringe patterns as a function of the optical path difference and, consequently, the linewidth of the laser. As a test laser, we use a tunable external cavity laser source at around 780 nm, where an interference filter is employed for wavelength selection. Data obtained by applying the interferometric technique to this laser and the analysis of these data, along with the resulting linewidth value, are presented. Given that the described measurement setup is inexpensive, straightforward, and pedagogically accessible, it is well-suited for an instructional physics laboratory experiment and will also be of interest to laboratory researchers. (c) 2024 Published under an exclusive license by American Association of Physics Teachers.
Downloadable publication This is an electronic reprint of the original article. |  | |
Downloadable publication This is an electronic reprint of the original article. | |
