Abstract-In-line single-mode tapered-fiber Mach-Zehnder interferometers (MZI-SMTF) with average waist diameters (davg) of 4.05 and 2.89 μm have been fabricated -and both the temperature and the humidity sensitivity of the surrounding media have been measured and compared. The humidity and temperature were measured over the ranges from 0% to 90% and 28 ºC to 40 ºC, respectively. The stability of the system at 50%RH and 90%RH were investigated while the temperature of the chamber was maintained at about 28 ºC. The humidity and temperature sensitivity resolution values were 0.02 nm/%RH and 0.05 nm/0.1ºC for the MZI-SMTF-1 with an average waist diameter of 4.05 μm -while they were 0.01 nm/%RH and 0.025 nm/0.1ºC for the MZI-SMTF-2 with an average waist diameter of 2.89 μm.

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In this work, a compact thulium-doped fiber laser with a Q-switched output is proposed and demonstrated. A thulium-doped fiber is used for the laser, with a peak absorption of 200 dB m−1 at 790 nm and a cutoff wavelength of 1350 nm as the primary gain medium, and a silver-based saturable absorber as the pulse generation mechanism. The pulses obtained from the proposed laser have repetition rates from 38.3 kHz up to 56.2 kHz, with a pulse width as low as 4.2 µs and pulse energy as high as 67.3 nJ at a maximum pump power of 228.8 mW. The generated pulses are highly stable, showing no changes or fluctuations over operation for a period of 60 min, and further validated with signal-to-noise ratios of 57.0 dB and 59.5 dB in the optical and frequency domains respectively. The proposed laser has high potential for eye-safe applications in manufacturing and medicine.

A thulium-doped fiber laser (TDFL) with a tunable Q-switched output is proposed and demonstrated. A silver nanoparticle based saturable absorber is used to generate the Q-switched pulses, while a tunable Mach-Zehnder filter acts as the wavelength-tuning mechanism. The TDFL has an operating wavelength range of 1916.5-1945.3 nm, with output pulses that have a repetition rate of 50.1 kHz and a pulse width of 5.1 µs, as well as a pulse energy of 69.3 nJ at the maximum pump power. The Q-switched pulses obtained are very stable and have a signal-to-noise ratio of 34.18 dB.