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

Abstract

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 Pr 3þ -doped laser operating directly in the green spectral region, addressing the aforementioned difficulties. The compact all-fiber laser consists of a double-clad Pr 3þ -doped fluoride fiber, two homemade fiber dichroic mirrors at visible wavelengths, and a 443-nm fiber-pigtailed pump source. Benefitting from > 10 MW∕cm 2 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.

Real‐Time Investigation of Ultrafast Dynamics through Time‐Stretched Dispersive Fourier Transform in Mode‐Locked Fiber Lasers

“…For instance, a 3.6 W continuous wave praseodymium‐doped green laser at ≈521 nm was demonstrated and supposed to achieve mode‐locking operation. [ 177 ] However, a challenge in stretching the spectral profile of visible MLFL is the high loss of dispersive media, i.e., SMF‐28e, DCF, and Hi1060 optical fiber in the visible region, which should be solved before the TS‐DFT techniques can be executed. In contrast to the real‐time investigation in near‐infrared region, the TS‐DFT technique has been seldom employed for the study of dynamics in both visible and mid‐infrared regions.…”

635 nm femtosecond fiber laser oscillator and amplifier

“…Currently, the majority of visible fiber lasers leverage rare-earth-doped fluoride fibers (e.g., Pr3+, 24 Ho3+, 25 Dy3+, 26 and Er3+ 27 ) as the efficient gain medium. Over the years, significant progress has been made in achieving wavelength-tunable, 28 – 30 high-power, 31 – 37 Q-switched, 38 – 40 and mode-locked 41 – 46 visible rare-earth-doped fluoride fiber lasers. Although it has been very well demonstrated in the near-infrared, femtosecond mode locking in visible fiber lasers remains extraordinarily challenging and has not yet been reported, except for one related work on 1.6 ps visible fiber oscillator compressed to 168 fs duration outside the oscillator by a grating pair 46 .…”

Effect of P/Al ratio on the X‐ray induced darkening in Dy‐doped silica glasses at visible wavelengths

“…Among laser system, fiber lasers show advantages in high beam quality and compact structure. Fluoride glass fiber is an attractive host for visible laser due to its broad transmission window from ultraviolet (UV) to mid‐infrared region, 10–13 and the Dy 3+ ‐doped fluoride fiber has demonstrated the continuous‐wave yellow laser with watt‐level output power (1.12 W) at 575 nm 14 . However, the difficulty of synthesis, poor mechanical strength, and degraded chemical stabilities have limited the practical applications of fluoride glass as host for fiber lasers.…”