Tunable wide spacing all-fiber dual-wavelength holmium-doped fiber laser using a Lyot filter operating above 2 μm

• Main Authors: Ahmad, Harith, Chiam, J. W., Samion, Muhamad Zharif, Zaini, Muhammad Khairol Annuar, Zulkifli, M. Z., Thambiratnam, K.
• Format: Article
• Published: IOP Publishing 2024
• Subjects: QC Physics
• Online Access: http://eprints.um.edu.my/44181/; https://doi.org/10.1088/1555-6611/ad109a

In this work, we successfully demonstrated an all-fiber, dual-wavelength holmium-doped fiber laser (HDFL) with a tunable wavelength spacing range of 8 nm to 24 nm. The HDFL utilizes a Lyot filter to obtain a stable dual wavelength output, with the Lyot filter being constructed from a polarizer, a 20 m polarizing maintaining fiber (PMF) and two polarization controllers (PCs). The dual-wavelength HDFL has an operating wavelength range from 2072.1 nm to 2097.2 nm and a maximum spacing of 24 nm between the lasing wavelengths as well as a signal-to-noise ratio of up to 45 dB and a side mode suppression ratio as low as 0.15 dB. The HDFL is highly stable, with the lasing output have a low power fluctuation of only 2.3 dB over a continuous operation period of 75 min. The proposed HDFL would have substantial applications as a low cost laser source for sensing applications beyond the 2 mu m region, particularly those that require a control signal.