Tunable passively Q-switched ultranarrow linewidth erbium-doped fiber laser

• Main Authors: Zulkifli, M. Z., Muhammad, F. D., Mohd. Azri, M. F., Mohd. Yusof, M. K., Hamdan, K. Z., Samsudin, S. A., Yasin, M.
• Format: Article
• Published: Elsevier B.V. 2020
• Subjects: TP Chemical technology
• Online Access: http://eprints.utm.my/id/eprint/91207/; http://dx.doi.org/10.1016/j.rinp.2020.102949
• Institution: Universiti Teknologi Malaysia

A tunable passively Q-switched erbium-doped fiber laser with ultranarrow linewidth is proposed and demonstrated. With the single wall carbon nanotubes (SWCNTs) as the passive Q-switch, the ultranarrow linewidth laser operation is realized based on spectral filtering effect. using an ultranarrow tunable bandpass filter (UNTBF). The Q-switched laser spectrum is tunable from 1525 to 1561 nm, covering a wavelength range of 36 nm. At 1545 nm, the highest repetition rate of ~38 kHz and the lowest pulse width of 1.15 μs are obtained, with the corresponding pulse energy of approximately 0.18 nJ. The linewidth measurement using self-heterodyne technique yields a linewidth value of 17.5 kHz, which may be the narrowest linewidth for a Q-switched fiber laser to the best of our knowledge.