Watt-level green random laser at 532  nm by SHG of a Yb-doped fiber laser

Abstract

We have developed a watt-level random laser at 532 nm. The laser is based on a 1064 nm random distributed ytterbium (Yb) gain-assisted fiber laser seed with a 0.35 nm linewidth and 900 mW polarized output power. A study for the optimal length of the random distributed mirror was carried out. A Yb-doped fiber master oscillator power amplifier architecture is used to amplify the random seeder laser without additional spectral broadening up to 20 W. By using a periodically poled lithium niobate crystal in a single-pass configuration, we generate in excess of 1 W random laser at 532 nm by second-harmonic generation (SHG) with an efficiency of 9%. The green random laser exhibits an instability <1%, an optical signal-to-noise ratio >70 dB, a 0.1 nm linewidth, and excellent beam quality.

Quasi-CW Pumping of a Single-Frequency Fiber Amplifier for Efficient SHG in PPLN Crystals with Reduced Thermal Load

“…The frequency conversion efficiency of CW 1064 nm in PPLN crystals has been shown to saturate when the output power generated at 532 nm exceeds 3 W [10, [16][17][18]27]. Therefore, our second-harmonic generation is performed only in the QCW mode.…”

“…These three reports all used a crystal length of 25 mm and CW excitation. In most reports of green generation in the CW mode using PPLN crystals and both a fundamental power higher than 7 W and an output power higher than 2.5 W at 532 nm [10,[16][17][18], gives rise to green-induced infrared absorption (GRIIRA). This effect causes damage to the material [19] and other thermal limitations such as thermal dephasing and thermal lensing, resulting in constraints of the conversion efficiency and deterioration of the generated beam quality.…”

Effect of Linewidth on the Relative Intensity Noise in Random Distributed Feedback Raman Fiber Lasers

“…Since distributed feedback in low-loss communication fibers is weak, even for spans of tens of kilometers, high amplification ratios are required in order to reach the lasing threshold. Raman amplification is a widespread solution given its distributed nature and the fact that it can be applied to any conventional optical fiber; however, other approaches, such as the use of doped fibers [ 4 ], Brillouin amplification [ 5 ], or a combination of all of them, also can be used [ 6 ] to achieve efficient lasing. Raman-based RDFLs offer stable stimulated emission in a spectral band of few nanometers, but this spectral behavior can be tailored to create multi-wavelength sources with linewidths of few picometers [ 7 ].…”

Statistical properties of Er/Yb co-doped random Rayleigh feedback fiber laser

“…RE-doped random fiber lasers can be constructed by combining the RE-doped active fiber and passive single-mode fiber (SMF), which provide the gain and the randomly distributed feedback, respectively [23][24][25] . RE-doped randomly fiber lasers can generate random lasing in different wavelength regions and have been used in several applications, such as the seed laser in a master oscillator power amplifier (MOPA) system [28,29] , the pump source for a cascaded Raman fiber laser [30] , supercontinuum generation [31] , frequency conversion [32] , and temporal ghost imaging [33] . In fact, the temporal dynamics property of RE-doped random fiber lasers is a crucial factor to determine the performance of the aforementioned applications, such as the spectral linewidth maintenance in MOPA [28,29] , the spectral purity of the cascaded Raman lasing [6] , and the spectral bandwidth and flatness of the supercontinuum source [31] .…”