Mode-locked fiber lasers at 1064 and 910 nm wavelengths using Nd^(3+)-doped silica fiber

Mode-locked lasing operations at 1064 and 910 nm wavelengths are demonstrated,respectively,in two all-fiber laser oscillators using our homemade Nd^(3+)-doped silica fiber(NDF)as the gain medium.The Al3+/Nd^(3+)co-doped silica core glass was fabricated by the modified sol-gel method with 18,300×10^(-6) Nd^(3+)doping concentration.The NDF drawn by the rodin-tube method has a core of 4μm in diameter and a numerical aperture(NA)of 0.14.At 1064 nm,we measure an average laser output power of 18mWwith a pulse duration of 5.75 ps,a pulse energy of 1.14 nJ,and a slope efficiency of 7.2%.Using the same NDF gain fiber of a different length,a maximum average laser output power is 3.1 mW at 910 nm with a pulse duration of 877 ns,a pulse energy of 2.7 nJ,and a slope efficiency of 1.44%.

3.6 W compact all-fiber Pr3+-doped green laser at 521 nm

Green semiconductor lasers are still undeveloped,so high-power green lasers have heavily relied on nonlinear frequency conversion of near-infrared lasers,precluding compact and low-cost green laser systems.Here,we report the first Watt-level all-fiber CW Pr3t-doped laser operating directly in the green spectral region,addressing the aforementioned difficulties.The compact all-fiber laser consists of a double-clad Pr3t-doped fluoride fiber,two homemade fiber dichroic mirrors at visible wavelengths,and a 443-nm fiber-pigtailed pump source.Benefitting from>10 MW∕cm2 high damage intensity of our designed fiber dielectric mirror,the green laser can stably deliver 3.62-W of continuous-wave power at∼521 nm with a slope efficiency of 20.9%.To the best of our knowledge,this is the largest output power directly from green fiber lasers,which is one order higher than previously reported.Moreover,these green all-fiber laser designs are optimized by using experiments and numerical simulations.Numerical results are in excellent agreement with our experimental results and show that the optimal gain fiber length,output mirror reflectivity,and doping level should be considered to obtain higher power and efficiency.This work may pave a path toward compact high-power green all-fiber lasers for applications in biomedicine,laser display,underwater detection,and spectroscopy.

Multiphoton process and optical amplification in Er^(3+)-Yb^(3+)-doped fiber pumped by Ti:Al_2O_3 tunable laser at 980-nm band

The .Er3+-Yb3+-doped fiber has a broadened absorption spectrum, which means the pumping sources can work efficiently from 810 to 1100nm. Among them 980nm is the maximum.absorption （10 dB/km） wavelength. By energy transferring and multiphoton process, the visible and ultraviolet radiation occurs when the Er3+-Yb3+-doped fiber is pumped by the laser at 980-nm band. Further researches on the mechanism of the fluorescence of Er3+-Yb3+-doped silica fiber pumped by Ti: A12O3 tunable laser at 980-nm band are helpful

Highly efficient actively Q-switched Er3+-doped ZBLAN fiber laser operating around 2.8μm usind a La3Ga5SiO14 electro-optical modulator

The mid-infrared (MIR) pulsed laser,operating at around 2.8μm,holds great significance due to its strong water absorption and the characteristic fingerprint spectra it provides for essential molecules.Nevertheless,the challenge of achieving stable MIR pulses persists,primarily due to the limited availability of reliable components operating in the MIR range.In this work,a La_(3)Ga_(5)SiO_(14)(LGS) crystal is used as the electro-optical modulator within the laser cavity constituted by an Er^(3+)-doped ZrF_(4)-BaF_(2)-LaF_(3)-AlF_(3)-NaF (ZBLAN) fiber,successfully generating Q-switched MIR lasing.This achievement is characterized by a low pump threshold,high slope efficiency,and adjustable repetition rate within the 2.8μm wavelength range.Stable pulses are attainable with long-term stability at a repetition rate of 18 kHz and a modest pump power of 0.6 W,and the maximum output power reaches 451 mW,featuring a pulse width of 64 ns at a pump power of 4.4 W,along with a slope efficiency of approximately 11.4%.It represents the highest efficiency in an electro-optical Q-switched laser operating around 2.8μm.Our research introduces an innovative active Q-switching approach to enhance the performance of MIR pulsed fiber lasers,thus advancing the development of MIR coherent sources and their associated applications.

Generation of 100 nJ pulse,1 W average power at 2μm from an intermode beating mode-locked all-fiber laser

We report on the investigation of intermode beating mode-locked(IBML)pulse generation in a simple all-fiber Tm^3+-doped double clad fiber laser(TDFL).This IBML TDFL is implemented by matching longitudinal-mode frequency between 793 nm laser and TDFL without extra mode locker.The central wavelength of 1983 nm,the fundamental pulse frequency of 9.6 MHz and the signal-to-noise ratio(SNR)of>50 dB are achieved in this IBML TDFL.With laser cavity optimization,the IBML TDFL can finally generate an average output power of 1.03 W with corresponding pulse energy of 107 nJ.These results can provide an easily accessible way to develop compact large-energy,highpower TDFLs.