Tunable Dual-Wavelength Thulium-Doped Fiber Laser Based on FBGs and a Hi-Bi FOLM

Abstract

Abstract-A tunable dual-wavelength thulium doped fiber laser is demonstrated experimentally. For the first time for the 2-µm wavelength band we propose the independent tuning of the generated laser lines based on fiber Bragg gratings and the use of a Hi-Bi fiber optic loop mirror for the fine adjustment of the cavity losses to obtain stable dual-wavelength operation. Dualwavelength laser generation with the laser lines separation in the range from 0.3 to 6.5 nm is obtained. The laser emission exhibits an optical signal-to-noise ratio better than 56 dB. Improved stability with output power fluctuations less than 1 dB is observed in dual-wavelength generation with equal power of lines.

Tunable dual-wavelength operation of an all-fiber thulium-doped fiber laser based on tunable fiber Bragg gratings

“…These techniques are based on the use of an optical device which allows the adjustment of the intra-cavity losses to reduce competition between the generated laser lines [14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. In our experience, we have demonstrated stable dual-wavelength laser emission of TDFL based on the use of a FOLM with Hi-Bi fiber loop [24,25]. The use of the Hi-Bi FOLM allows the fine adjustment of the cavity losses between the generated laser lines with stability improvement.…”

“…The use of the Hi-Bi FOLM allows the fine adjustment of the cavity losses between the generated laser lines with stability improvement. The proposed method has been demonstrated for fiber laser configurations which include the use of FBGs for selection and tuning of the generated laser lines [24].…”

“…The TFBGs are used as narrow band reflection spectral filters with maximal reflection at central wavelengths of 2069.30 nm for TFBG1 and 2069.44 nm for TFBG2. The FBGs are placed on a mechanical device which allows strain application on the FBGs by a micrometric screw displacement as it was reported in [24]. The VOAs were placed to independently adjust the cavity losses for each generated laser line by the TFBGs.…”

“…Moreover, the wide gain spectrum of the TDF makes TDFLs attractive for their application as widely tunable laser sources in optical instrumentation, microwave photonics, and terahertz generation at the 2 μm region. Several methods to obtain tunable laser emission in TDFL have been reported, where the wavelength tuning of the generated laser line is based on different fiber devices such as Hi-Bi FBGs [14][15][16][17][18][19][20], tunable filters [21][22][23], fiber optical loop mirrors (FOLMs) [24,25], and PCs [26][27][28]. In this regard, FBGs have proved their reliability as spectral filters for wavelength selection and tuning in fiber laser approaches.…”

Tandem-pumped, tunable thulium-doped fiber laser in 21 μm wavelength region

“…Conventionally, Tm-doped fiber lasers were pumped at 792 nm ( 3 H 6 → 3 F 4 transition), allowing for direct diode pumping and offering high conversion efficiencies due to the 2-for-1 cross-relaxation process of the Tm ions [14,17,18]. Alternatively, Tm-doped fiber lasers were also pumped at around 1565 nm ( 3 H 6 → 3 H 4 transition) by Er-doped fiber lasers with a diffraction-limited beam [15,[19][20][21], with the advantages of high Stocks efficiency and hence low quantum-defect-induced heat generation. A Tm-doped fiber laser could also be tandempumped by another Tm: fiber laser at > 1900 nm, since the absorption band of a Tm-doped silica fiber related to the 3 H 6 → 3 H 4 transition extends up to > 1900 nm [12], thus allowing for higher Stocks efficiency and further reduction of quantum-defect-induced heat generation [22][23][24][25].…”