Linewidth-Narrowed, Linear-Polarized Single-Frequency Thulium-Doped Fiber Laser Based on Stimulated Brillouin Scattering Effect

Wavelength-Switchable Single-Longitudinal- Mode Thulium-Doped Fiber Laser With Sampled Fiber Bragg Grating

“…It should be noted that the laser at λ2 achieved the widest linewidth due to widest 3-dB bandwidth of the reflection peak of the filter at λ2. These laser linewidths are narrower than those of previous reports [4,6,16,[32][33][34] .…”

“…The proposed SLM TDFL is compared with different SLM TDFLs recently proposed, which is shown in Table II. The ONSR of the proposed fiber laser is larger than that in [34], lower than that in [32,33]. The linewidth is narrower that in [32][33][34].…”

Power scaling and spectral linewidth suppression of hybrid Brillouin/thulium fiber laser

“…Although two similar trends were observed with 793-nm cladding pump and 1570-nm core pump, respectively, the linewidths with 793-nm cladding pump were much broadened than that with the 1570-nm core pump, which is attributed to the inferior noise performance of multimode 793-nm LD and relatively less quantum defect of 1570-nm core pump. The intrinsic noise of multimode 793-nm LD is much larger than that of single-mode 1570-nm fiber laser, which will be introduced into the ring cavity through pumping process and impose adverse effects on linewidth narrowing effect [29,30]. In addition, quantum defect is the dominant factor of thermal noise contributing to the linewidth broadening, therefore, linewidth can be further narrowed with 1570-nm core pump resulting from lower thermal noise.…”

“…The Stokes light could be generated with Brillouin pump of only 0.5 mW and the SBS threshold was about 10 mW in terms of the 980-nm laser diode (LD) power. Until now, many researches have been reported about BEFLs and hybrid Brillouin/ytterbium lasers (BYFLs) [25][26][27][28][29][30]. Guan et al and Chen et al have studied the power performance of BYFL and BEFL, respectively, in which the influences of Brillouin pump power, output coupling and length of active fiber on power performance have been investigated experimentally and theoretically and it was found that the output power of first-order Stokes is limited by higher-order SBS [25,26].…”

“…In the 2 µm region, a BTFL was reported in 2017, in which the resulting threshold in terms of the Brillouin pump was lower to 200 mW and the maximum Stokes power of 205 mW was achieved. A linewidth of 4.6 kHz was obtained with a narrowed degree of 8 times, which was limited by the noise of multimode 793-nm pump source [29]. However, the power performance and linewidth narrowing effect of BTFLs at 2 µm have not been systematically investigated.…”