Fluorotellurite Microstructured Fibers Research Articles

8.08 W holmium doped fluorotellurite fiber laser at 2067 nm

We reported a multi-watt ~2.1 µm laser output from a 30 cm long Ho3+-doped fluorotellurite microstructured fiber (FTMF) pumped by a homemade 1980 nm Tm3+-doped silica fiber laser. When the pump power was increased to 61.8 mW, lasing at 2067 nm was achieved from the Ho3+-doped FTMT, and an unsaturated maximum output power of ~8.08 W was obtained for a pump power of ~10.56 W. The corresponding slope efficiency was about 77.21%. During our experiments, no obvious damage was observed on the end face of the Ho3+-doped FTMF. Our results indicated that Ho3+-doped fluorotellurite fibers had the potential for constructing high power fiber lasers at 2.1 µm.

Design of Fluorotellurite Microstructured Fibers With Near-Zero-Flattened Dispersion Profiles for Optical-Frequency Comb Generation

We present the design of fluorotellurite microstructured fibers (FTMFs) with near-zero-flattened dispersion profiles in the wavelength range of 1500–1600 nm for optical frequency comb (OFC) generation. The FTMFs are based on TeO2-BaF2-Y2O3 glass with a zero-dispersion wavelength of ∼2160 nm. The fiber core is surrounded by the two layers of air holes. The addition of large size air holes in the outer layer is to shift the zero-dispersion wavelength of the fiber from ∼2160 nm to the wavelength region of 1500–1600 nm. The addition of small size air holes in the inner layer is to make the dispersion profile of the fiber become flat in the wavelength range of 1500–1600 nm. By optimizing the parameters (the core diameter, the air hole size, the pitch of air holes, etc.) of FTMFs, the fiber with the chromatic dispersion value between −0.5 and 0.3 ps/nm/km in the wavelength range of 1500–1600 nm is achieved. Furthermore, numerical simulations are used to show the potential of the fiber for OFC generation via cascaded four-wave mixing. Flat top OFC extending from 1500 to 1600 nm with tunable mode spacing from 25 to 100 GHz can be generated in a 2-m-long fiber by using a 1550-nm laser with a pulse width of 0.85 ps and a peak power of 49 W as the pump source. The effects of stimulated Brillouin scattering on OFC generation are also investigated.

Enhancement of phase-matched third harmonic generation via soliton self-frequency shift cancellation in a fluorotellurite microstructured fiber

We report the enhancement of phase-matched third harmonic generation (THG) via soliton self-frequency shift cancellation (SSFSC) in a fluorotellurite microstructured fiber (FTMF) pumped by a 1560 nm femtosecond fiber laser. The FTMF has two zero-dispersion wavelengths of 891 and 2012 nm for its slow axis. As the pump laser is polarized along the slow axis of the FTMF, phase matched THG at 629 nm is observed in the FTMF when the Raman soliton red-shifts to 1913 nm and the effective index at 1913 nm for the fundamental propagation mode matches with that at 629 nm for the high order propagation mode for a pump power of ∼25.2 mW. Interestingly, the THG at 629 nm is enhanced very much when the Raman soliton meets the second zero-dispersion wavelength of the slow axis and further SSFSC occurs with increasing the pump power. Such an enhancement is due to the unchanged operating wavelength of the Raman soliton with an increase in the pump power when SSFSC occurs and the resulting increase in the interaction length between the Raman soliton and third harmonic. Our results show that high efficient THG with a designed wavelength can be obtained via SSFSC in dispersion engineered optical fibers.

1887 nm lasing in Tm3+-doped TeO2-BaF2-Y2O3 glass microstructured fibers

In this paper, we demonstrate ∼2 μm lasing in Tm3+-doped fluorotellurite microstructured fibers. The Tm3+-doped fibers are based on TeO2-BaF2-Y2O3 glasses and fabricated by using a rod-in-tube method. Under the pump of a 1570 nm Er3+-doped fiber laser, lasing at 1887 nm is obtained in a ∼42.5 cm long Tm3+-doped fiber with a threshold pump power of 94 mW. As the pump power increases to 780 mW, the obtained maximum unsaturated power reaches up to ∼408 mW with a slop efficiency of ∼58.1%. This result indicates that the Tm3+-doped fluorotellurite fibers are promising gain media for ∼2 μm fiber lasers.

Coherent supercontinuum generation from 1.4 to 4 μm in a tapered fluorotellurite microstructured fiber pumped by a 1980 nm femtosecond fiber laser

Coherent supercontinuum light expanding from 1.4 to 4 μm is generated in a 4 cm long tapered fluorotellurite microstructured fiber (MF) pumped by a 1980 nm femtosecond fiber laser. The spectral broadening in the tapered fluorotellurite MF is caused by self-phase modulation, the Raman soliton, and red-shifted dispersive wave generation. Our results show that tapered fluorotellurite MFs are promising nonlinear medium for generating coherent broadband mid-infrared supercontinuum light.

Supercontinuum generation from 437 to 2850 nm in a tapered fluorotellurite microstructured fiber

We demonstrated supercontinuum (SC) generation in a tapered fluorotellurite microstructured fiber (MF) with a sub-micrometer core diameter. Fluorotellurite MFs based on TeO2–BaF2–Y2O3 glasses were fabricated by using a rod-in-tube method and a tapered fluorotellurite MF with a minimum core diameter of ~0.65 µm was prepared by employing a tapering system. A 1560 nm femtosecond fiber laser was used as the pumping source. With increasing the peak power of the launched pump laser to ~11 kW, SC light expanding from 437 to 2850 nm was generated in the tapered fluorotellurite MF. In addition, relatively strong blue-shifted dispersive wave at ~489 nm was also observed from the tapered fluorotellurite MF.

Mid-infrared dispersive waves generation in a birefringent fluorotellurite microstructured fiber

Tunable mid-infrared dispersive waves are generated in a birefringent fluorotellurite microstructured fiber (FTMF) pumped by a 1560 nm femtosecond fiber laser. The FTMF have two zero-dispersion wavelengths (ZDWs) for each polarization axis. The second ZDWs for the fast and slow axes of the FTMF are 2224 and 2042 nm, respectively. As the pump laser is polarized along the fast (or slow) axis of the FTMF, tunable mid-infrared dispersive waves from 2680 to 2725 nm (or from 2260 to 2400 nm) are generated in the FTMF when the Raman soliton meets the second zero-dispersion wavelength of the fast (or slow) axis with increasing the pump power. Our results show that the designed FTMFs are promising nonlinear media for generating tunable mid-infrared light sources.

2.074- Lasing From Ho3+-Doped Fluorotellurite Microstructured Fibers Pumped by a 1120-nm Laser

We demonstrate 2.074- $\mu \text{m}$ lasing from Ho3+-doped fluorotellurite microstructured fibers (FTMFs) pumped by a 1120-nm Yb3+-doped fiber laser. Ho3+-doped FTMFs based on TeO2–BaF2–Y2O3 glasses are fabricated by using a rod-in-tube method. With increasing the pump power to 253 mW, lasing at 2.074 $\mu \text{m}$ is achieved from a 42-cm-long Ho3+-doped FTMF. With further increasing the pump power to 1015 mW, a maximum unsaturated power of 98 mW is obtained, and the corresponding slope efficiency is up to 12.4%. In addition, relatively strong 1.2- and 2.9- $\mu \text{m}$ emissions are also observed from the Ho3+-doped FTMF.

Tapered fluorotellurite microstructured fibers for broadband supercontinuum generation.

Fluorotellurite microstructured fibers (MFs) based on TeO2-BaF2-Y2O3 glasses are fabricated by using a rod-in-tube method. Tapered fluorotellurite MFs with varied transition region lengths are prepared by employing an elongation machine. By using a tapered fluorotellurite MF with a transition region length of ∼3.3 cm as the nonlinear medium and a 1560 nm femtosecond fiber laser as the pump source, broadband supercontinuum generation covering from 470 to 2770 nm is obtained. The effects of the transition region length of the tapered fluorotellurite MF on supercontinuum generation are also investigated. Our results show that tapered fluorotellurite MFs are promising nonlinear media for generating broadband supercontinuum light expanding from visible to mid-infrared spectral region.

Holmium-doped fluorotellurite microstructured fibers for 2.1 μm lasing.

Holmium (Ho3+)-doped fluorotellurite microstructured fibers based on TeO2-BaF2-Y2O3 glasses are fabricated by using a rod-in-tube method. By using a 1.992 μm fiber laser as the pump source, lasing at 2.077 μm is obtained from a 27 cm long Ho3+-doped fluorotellurite microstructured fiber. The maximum unsaturated power is about 161 mW and the corresponding slope efficiency is up to 67.4%. The influence of fiber length on lasing at 2.1 μm is also investigated. Our results show that Ho3+-doped fluorotellurite microstructured fibers are promising gain media for 2.1 μm laser applications.