The mechanism of femtosecond optical pulse generation in a self-starting Er3+ -doped fiber ring soliton laser and experimental research results are discussed. Using the nonlinear polarization rotation effect of the fi...The mechanism of femtosecond optical pulse generation in a self-starting Er3+ -doped fiber ring soliton laser and experimental research results are discussed. Using the nonlinear polarization rotation effect of the fiber for sat-urable absorbers (and then self-amplitude modulation) which acts as the mode locking mechanism in an Er3+ -doped fiber ring cavity laser, stable self-starting mode locking pulses have been generated. The shortest output pulse is 269 fs, with the central wavelength of 1.531 @m at the repetition rate of 21.37 MHz. The average output powers of the two terminators of the laser are 0.25 mW and 0.08 mW respectively. The threshold pump power which sustains the mode locking is 15 mW. Under high pump power, the laser works in a high order harmonic mode locking state. The mode locking pulse durations vs different cavity lengths are also studied.展开更多
The modeling of rare-earth-doped fiber amplifier is accomplished by utilizing the rate and propagation equations of distinct levels for a laser medium. A complex theoretical model for neodymium (Nd3+), erbium (Er...The modeling of rare-earth-doped fiber amplifier is accomplished by utilizing the rate and propagation equations of distinct levels for a laser medium. A complex theoretical model for neodymium (Nd3+), erbium (Er3+), thulium (Tm3+) and ytterbium (Yb3+) codoped telluride glass fiber covering 0.4--2.0 μm emission spectra is presented. The emission spectra of Nd3+-Er3+-Tm3+-yb3+ codoped telluride fiber are realized with the excitation of both 808 and 980 nm lasers pumped at 500 mW. Numerical methods are used to calculate the emission spectra covering 0.4--2.0 μm. With the Nd3+, Tm3+ and Yb3+ ion concentrations fixed at 2 x 1020 ion/m3, the Er3+ ion concentration optimized to 8 x 10^20 ion/m3 and the fiber length spanning from 0.5 to 2 m, a peak amplified spontaneous emission (ASE) power of 19.8 mW is attainable, and a minimum ASE power of 7.96 mW can also be achieved. The analytical techniques and results indicate that when a telluride codoped fiber with suitable ion concentrations of Nd3+, Er3+, Tm3+ and Yb3+ is excited by both 980 and 808 nm pump lasers, 0.4-2.0 μm emission spectra are attainable for vast optical applications.展开更多
In this work wavelength sensitivity in mechanically induced long period fiber gratings (MLPFG) is analyzed. This analysis is first carried out both in standard single-mode fiber SMF-28 and in Er-doped fibers. The mech...In this work wavelength sensitivity in mechanically induced long period fiber gratings (MLPFG) is analyzed. This analysis is first carried out both in standard single-mode fiber SMF-28 and in Er-doped fibers. The mechanical analysis for both types of fibers under different torsion conditions is presented. In order to apply the torsion one of the fiber ends is fixed while torsion is applied on the other end. A MLPFG whose period is 503 μm is used to press the fiber after torsion is applied. This allows for micro curvatures to be formed on the fiber, which in turn generates a periodical index perturbation on it. Here, it was noted that the sensitive wavelength shift of the rejection bands is bigger for Er-doped fibers. For a torsion of 6 turns applied to 10 cm of doped fiber the wavelength peaks can be moved up to 25 nm, which is longer to what was detected on standard fibers. Therefore, by using Er-doped fibers to monitor torsion on structures will give more sensitive and accurate results than using standard fibers. These results can be employed for sensing applications, especially for small to medium size structures, which can be mechanical, civil or aeronautics.展开更多
We report on a chalcogenide glass fiber doped with Pr^(3+) that can be used for commercialized 1.5-μm and 2-μm laser excitations by emitting broadband 3 μm–5.5 μm fluorescence, which is extruded into a preform an...We report on a chalcogenide glass fiber doped with Pr^(3+) that can be used for commercialized 1.5-μm and 2-μm laser excitations by emitting broadband 3 μm–5.5 μm fluorescence, which is extruded into a preform and then drawn into a step-index fiber. The spectroscopic properties of the fiber and glass are reported, and the mid-infrared fiber lasers are also numerically investigated. Cascade lasing is employed to increase the inversion population of the upper laser level. The particle swarm approach is applied to optimize the fiber laser parameters. The output power can reach 1.28 W at 4.89-μm wavelength, with a pump power of 5 W, excitation wavelength at 2.04 μm, Pr^(3+) ion concentration at 4.22 × 10^(25) ions/m^3,fiber length at 0.94 m, and fiber background loss at 3 dB/m.展开更多
基金Project supported by Major Project of Chinese Academy of Sciences (No. KJ952-J1-705).
文摘The mechanism of femtosecond optical pulse generation in a self-starting Er3+ -doped fiber ring soliton laser and experimental research results are discussed. Using the nonlinear polarization rotation effect of the fiber for sat-urable absorbers (and then self-amplitude modulation) which acts as the mode locking mechanism in an Er3+ -doped fiber ring cavity laser, stable self-starting mode locking pulses have been generated. The shortest output pulse is 269 fs, with the central wavelength of 1.531 @m at the repetition rate of 21.37 MHz. The average output powers of the two terminators of the laser are 0.25 mW and 0.08 mW respectively. The threshold pump power which sustains the mode locking is 15 mW. Under high pump power, the laser works in a high order harmonic mode locking state. The mode locking pulse durations vs different cavity lengths are also studied.
基金the National Natural Science Foundation of China(Nos.60377023 and 60672017)the Program for New Century Excellent Talents in Universities(NCET)Shanghai Optical Science and Technology Project(No.05DZ22009)
文摘The modeling of rare-earth-doped fiber amplifier is accomplished by utilizing the rate and propagation equations of distinct levels for a laser medium. A complex theoretical model for neodymium (Nd3+), erbium (Er3+), thulium (Tm3+) and ytterbium (Yb3+) codoped telluride glass fiber covering 0.4--2.0 μm emission spectra is presented. The emission spectra of Nd3+-Er3+-Tm3+-yb3+ codoped telluride fiber are realized with the excitation of both 808 and 980 nm lasers pumped at 500 mW. Numerical methods are used to calculate the emission spectra covering 0.4--2.0 μm. With the Nd3+, Tm3+ and Yb3+ ion concentrations fixed at 2 x 1020 ion/m3, the Er3+ ion concentration optimized to 8 x 10^20 ion/m3 and the fiber length spanning from 0.5 to 2 m, a peak amplified spontaneous emission (ASE) power of 19.8 mW is attainable, and a minimum ASE power of 7.96 mW can also be achieved. The analytical techniques and results indicate that when a telluride codoped fiber with suitable ion concentrations of Nd3+, Er3+, Tm3+ and Yb3+ is excited by both 980 and 808 nm pump lasers, 0.4-2.0 μm emission spectra are attainable for vast optical applications.
文摘In this work wavelength sensitivity in mechanically induced long period fiber gratings (MLPFG) is analyzed. This analysis is first carried out both in standard single-mode fiber SMF-28 and in Er-doped fibers. The mechanical analysis for both types of fibers under different torsion conditions is presented. In order to apply the torsion one of the fiber ends is fixed while torsion is applied on the other end. A MLPFG whose period is 503 μm is used to press the fiber after torsion is applied. This allows for micro curvatures to be formed on the fiber, which in turn generates a periodical index perturbation on it. Here, it was noted that the sensitive wavelength shift of the rejection bands is bigger for Er-doped fibers. For a torsion of 6 turns applied to 10 cm of doped fiber the wavelength peaks can be moved up to 25 nm, which is longer to what was detected on standard fibers. Therefore, by using Er-doped fibers to monitor torsion on structures will give more sensitive and accurate results than using standard fibers. These results can be employed for sensing applications, especially for small to medium size structures, which can be mechanical, civil or aeronautics.
基金Project supported by the Young Scientists Fund of the National Natural Science Foundation of China(Grant No.61605095)the Natural Science Foundation of Zhejiang Province,China(Grant No.LY19F050004)+2 种基金the Natural Science Foundation of Ningbo City(Grant No.2015A610038)the Open Fund of the Guangdong Engineering Technology Research and Development Center of Special Optical Fiber Materials and Devices(South China University of Technology)(Grant No.2016-4)the K C Wong Magna Fund at Ningbo University
文摘We report on a chalcogenide glass fiber doped with Pr^(3+) that can be used for commercialized 1.5-μm and 2-μm laser excitations by emitting broadband 3 μm–5.5 μm fluorescence, which is extruded into a preform and then drawn into a step-index fiber. The spectroscopic properties of the fiber and glass are reported, and the mid-infrared fiber lasers are also numerically investigated. Cascade lasing is employed to increase the inversion population of the upper laser level. The particle swarm approach is applied to optimize the fiber laser parameters. The output power can reach 1.28 W at 4.89-μm wavelength, with a pump power of 5 W, excitation wavelength at 2.04 μm, Pr^(3+) ion concentration at 4.22 × 10^(25) ions/m^3,fiber length at 0.94 m, and fiber background loss at 3 dB/m.