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The 1550 nm band semiconductor optical amplifier (SOA) has great potential for applications such as optical communication. Its wide-gain bandwidth is helpful in expanding the bandwidth resources of optical communication, thereby increasing total capacity transmitted over the fiber. Its relatively low cost and ease of integration also make it a high-performance amplifier of choice for LiDAR applications. In recent years, with the rapid development of quantum-well (QW) material systems, SOAs have gradually overcome the shortcomings of polarization sensitivity and high noise. The research on quantum-dot (QD) materials has further improved the noise characteristics and transmission loss of SOAs. The design of special waveguide structures—such as plate-coupled optical waveguide amplifiers and tapered amplifiers—has also increased the saturation output power of SOAs. The maximum gain of the SOA has been reported to be more than 21 dB. The maximum saturation output power has been reported to be more than 34.7 dBm. The maximum 3 dB gain bandwidth has been reported to be more than 120 nm, the lowest noise figure has been reported to be less than 4 dB, and the lowest polarization-dependent gain has been reported to be 0.1 dB. This study focuses on the improvement and enhancement of the main performance parameters of high-power SOAs in the 1550 nm band and introduces the performance parameters, the research progress of high-power SOAs in the 1550 nm band, and the development and application status of SOAs. Finally, the development trends and prospects of high-power SOAs in the 1550 nm band are summarized. [ABSTRACT FROM AUTHOR]

High-power femtosecond mid-infrared (MIR) lasers are of vast importance to both fundamental research and applications. We report a high-power femtosecond master oscillator power amplifier laser system consisting of a single-mode Er:ZBLAN fiber mode-locked oscillator and pre-amplifier followed by a large-mode-area Er:ZBLAN fiber main amplifier. The main amplifier is actively cooled and bidirectionally pumped at 976 nm, generating a slope efficiency of 26.9%. Pulses of 8.12 W, 148 fs at 2.8 µm with a repetition rate of 69.65 MHz are achieved. To the best of our knowledge, this is the highest average power ever achieved from a femtosecond MIR laser source. Such a compact ultrafast laser system is promising for a wide range of applications, such as medical surgery and material processing. [ABSTRACT FROM AUTHOR]

• First demonstration of an all-polarization-maintaining continuous-wave fiber master oscillator power amplifier (MOPA) system at ∼1540 nm. • Experimental results closely followed simulation results based on Erbium-Ytterbium co-doped fiber (EYDF) design. • Achieved >20 W output power, ∼1.4 kHz linewidth, excellent power stability (<0.2 % RMS), and low intensity noise (−110 dBc/Hz). We have developed both theoretically and experimentally an all polarization-maintaining fiber-based master oscillator power amplifier (MOPA) system, which allows for amplifying the single-frequency continuous-wave (CW) fiber laser to >20 W without compromising the laser intensity noise (−110 dBc/Hz@ relaxation oscillation peak) at the specific wavelength of ∼1540 nm. The experimental results agree well with the simulated results. To the best of our knowledge, this is the first demonstration of a ∼1540-nm single-frequency all fiber laser and reaching such a high-power level. The amplified laser features a narrow linewidth of ∼1.4 kHz and a spectral side-mode-suppression ratio of >38 dB, even as the laser wavelength is tuned from 1538.216 nm to 1540.616 nm. It is believed to be the narrowest laser linewidth realized in the <1550-nm wavelength band of an Erbium-Ytterbium co-doped fiber MOPA system. The all polarization-maintaining configuration of the MOPA ensures the amplified laser linearly polarized with the polarization extinction ratio of >22 dB and power root mean square fluctuations of <0.2 %@1h. This high-performance single-frequency fiber laser is expected to be an ideal pump source in the spin-exchange relaxation-free (SERF)-based atomic sensors after second harmonic generation. [ABSTRACT FROM AUTHOR]

• L-band dissipative soliton NALM laser • Ultrafast L-band MOPA system with watt-level output power. • Gneration of L-band fs noise-like pulses in the amplifier. • A broad mid-infrared supercontinuum from 0.87 μm to 3.75 μm. Here, we propose a high power dissipative soliton (DS) laser with a central wavelength of ∼1612 nm. The whole laser system includes the mode-locking oscillator and the corresponding master oscillator power amplifier (MOPA). The mode-locking oscillator is a nonlinear amplifier loop mirror (NALM) cavity, which has a net normal dispersion enabling the generation of nJ-level DS pulses. To further enhance the output power of the 1.6 μm DS pulses, the specially-designed MOPA system consisting of multiple-stage single-pass amplifier is constructed, which can amplify the output power to watt level and meanwhile keeps a high suppression ratio to C-band amplified spontaneous emission (ASE). This high power 1.6 μm DS laser will have further applications in biomedical research and material processing. In the amplifier, we observe the automatic evolution of the DS pulses into the noise-like (NL) pulses under high pumping strength. At the maximum pump power, the MOPA system delivers the NL pulses with an output power of over 2 W. The narrowest spike duration is ∼70 fs (fs). This 1.6 μm fs-scale NL laser is a good pump source for generating the mid-infrared supercontinuum without short wavelength region loss. To demonstrate the superiority of this NL laser, a broad supercontinuum from ∼0.87 μm to ∼3.75 μm waveband is achieved with a piece of highly germanium-doped (Ge-doped) fiber. [ABSTRACT FROM AUTHOR]

We present a voltage driven traveling-wave model for the simulation of an integrated three-section master oscillator power amplifier. The model considers the applied voltage to each active section as an input parameter and calculates the longitudinal profiles of the local current and carrier densities. The model reproduces the experimental evidence of either a positive current when the section is acting as an amplifier or a negative current when it is acting as a photodiode in the photovoltaic mode. We validate the model by comparing with experimental results obtained both, under static operation for a variety of biasing conditions and under direct modulation. [ABSTRACT FROM AUTHOR]

Watt-class visible laser light with a high luminance can be created with high-power GaAs-based lasers either directly in the red spectral region or using single-pass second harmonic generation (SHG) for the colors in the blue-yellow spectral region. The concepts and results of red- and near infrared-emitting distributed Bragg reflector tapered lasers and master oscillator power amplifier systems as well as their application for SHG bench-top experiments and miniaturized modules are presented. Examples of these high-luminance light sources aiming at different applications such as flying spot display or holographic 3D cinema are discussed in more detail. The semiconductor material allows an easy adaptation of the wavelength allowing techniques such as six-primary color 3D projection or color space enhancement by adding a fourth yellow color. [ABSTRACT FROM AUTHOR]

• Wavelength tunable dissipative soliton resonance is realized in an all polarization maintaining Yb-doped fiber laser. • Based on a pulse picker, the repetition rate of pulses can be changed from 100 kHz to 3.6 MHz. • A record pulse peak power of 1.91 MW at 100 kHz for pulse width of 55 ps is achieved after amplification and compression. High peak power dissipative soliton resonance (DSR) with tunable wavelength and flexible repetition rate is experimentally achieved based on an all polarization maintaining master oscillator power amplifier fiber laser. The figure-of-eight oscillator outputs DSR pulse at a fundamental repetition rate of 3.6 MHz with square-shaped temporal pulse duration of 600 ps. By adjusting the intracavity fiber filter, the center wavelength of the DSR pulse can be continuously changed from 1017 to 1042 nm. These wavelength and temporal duration tunable pulses are then coupled into an all-fiber pulse picker to gain another tuning freedom of repetition rate from 100 kHz to 3.6 MHz. Seeded by the flexible pulse, an two-stage all-fiber amplifier is used to boost the average power to 20 W with the polarization extinction ratio of 18.2 dB. After compression, a record pulse peak power of 1.91 MW is achieved at the repetition rate of 100 kHz with pulse duration of 55 ps. [ABSTRACT FROM AUTHOR]

We report a compact, all fiber, 150 ps fiber master oscillator power amplifier operating at 1064 nm that has the ability of producing a maximum average output power of 2.16 W with peak power as high as 10 kW. The output from the master oscillator power amplifier is spliced with a highly nonlinear photonic crystal fiber, generating a supercontinuum with an average power of 250 mW at repetition rate of 1 MHz and spectrum bandwidth spanning from 600 to 1700 nm. The developed supercontinuum system is used to detect the presence of heavy metal contaminants in water by a simple light transmittance method to ensure that the water is free from heavy metal contaminants and safe for consumption. The supercontinuum laser source was shone onto a water sample with a detector placed at another end in order to measure the transmitted supercontinuum light. By measuring the amount of light attenuated at particular wavelength, the concentration of heavy metal contaminants present in the water sample could be determined. [ABSTRACT FROM AUTHOR]

We present a micro-integrated laser module based on an amplified diode laser and second harmonic generation which is a promising candidate for a green light source in next-generation 3D holographic displays. The light emitted by the amplified laser has a wavelength of 1064 nm, reaches a power up to 8.2 W and has a long coherence length of >400 m. For second harmonic generation, we tested two geometries of periodically poled lithium niobate crystals in single pass: a bulk crystal and a planar waveguide crystal. With the planar waveguide crystal, we achieve an output power >900 mW and a coherence length >20 m at a wavelength of 532 nm. [ABSTRACT FROM AUTHOR]

Red-emitting lasers for display applications require high output powers and a high visibility. We demonstrate diode lasers and modules in the red spectral range based on AlGaInP with optical output powers up to 1 W and a nearly diffraction limited beam. These high-luminance light sources based on tapered lasers are well suited for laser TVs and projectors for virtual reality simulators based on the flying spot technology. Additionally, we developed diode lasers with internal distributed Bragg reflector (DBR) surface gratings. These DBR tapered lasers and master-oscillator power-amplifiers based on DBR ridge-waveguide lasers and tapered amplifiers feature high power, single mode emission with coherence lengths up to several meters, which are suitable for the next-generation 3D displays based on holography. [ABSTRACT FROM AUTHOR]

We present a high compact structure laser diode (LD) side-pumped all-solid-state Q-switched master oscillator power amplifier (MOPA) laser system with high beam quality. Bidirectional voltage-supplied Q-switched and MOPA technologies were introduced in the design. An in-center wavelength of 1064 nm with pulse width adjustability from 5 to 18 ns was obtained at the repetition rate of 500 Hz. Through multistage Nd:YAG amplifiers at the pulse width of 6 ns, the oscillator was scaled up to 145 W and the corresponding peak power reached 48.3 MW with single pulse energy fluctuation less than 0.45% in 1 h operation. [ABSTRACT FROM AUTHOR]

Abstract: We have developed models to investigate the power properties of monolithic fiber laser with master oscillator multi-stage power amplifiers configuration. In the simulation the effect of optical characteristics of fiber fusion splice was considered, which was introduced by connecting fiber amplifiers. The theoretical modeling was established based on the classic theory of rate equations and the computational method was described in detail. On the basis of three high-power fiber lasers with different structures, we analyzed the splice loss and return loss, and how they influence the distribution of laser power in the system. The results showed that, on the present splicing level, both the enhancement of the pump capacity of fiber laser and the reduction of the quantity of power amplifier modules were effective strategies to accomplish fiber laser with tens of thousands of watts output. [Copyright &y& Elsevier]

Abstract: In this work, the small signal gain (γ 0) and signal saturation power (P sat) of a continuous wave (CW) single-frequency ytterbium-doped (YD) double-clad (DC) fiber master oscillator power amplifier (MOPA) array has been determined in the optimum length. At first, we have obtained output versus input signal powers in the amplifier, using the coupled steady-state rate equations for the various end diode pumping such as co/counter propagation and bidirectional modes. On the other hand, the steady-state amplification relation was employed at a presumed γ 0 and P sat as initial guess, to generate output signals. Then, using the least square method (LSM), those input/output signal powers were fitted by the best regression curve obtained from the amplification relation to determine the converged γ 0 and P sat values. The analytical formulae for γ 0 and P sat were derived using the rate equations as well. [Copyright &y& Elsevier]

In this article, we report an all-fiber master oscillator power amplifier (MOPA) system, which can provide high repetition rate and nanosecond pulse with diffraction-limit. The system was constructed using a (2 + 1) × 1 multimode combiner. The Q-Switched, LD pumped Nd:YVO4 solid-state laser was used as master oscillator. The 976-nm fiber-coupled module is used as pump source. A 10-m long China-made Yb3+-doped D-shape double-clad large-mode-area fiber was used as amplifier fiber. The MOPA produced as much as 20-W average power with nanosecond pulse and near diffraction limited. The pulse duration is maintained at about 15 ns during 50–175 kHz. The system employs a simple and compact architecture and is therefore suitable for the use in practical applications such as scientific and military airborne LIDAR and imaging. Based on this system, the amplification performances of the all-fiber amplifier is investigated. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2546–2549, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23770 [ABSTRACT FROM AUTHOR]

Abstract: A theoretical study for ultraviolet upconversion fiber master oscillator power amplifier (MOPA) based on the transition from the 4f5d state to the 3H4 ground state in Pr3+:ZBLAN fiber is performed by using steady population rate equations and propagation equations. The variation of the output power with the fiber length of master oscillator and MOPA and the launched pump powers, the dependence of the slope efficiency on the fiber length of master oscillator and MOPA, and the optimum fiber length of MOPA as a function of the launched pump powers, are calculated. Both the output power and the slope efficiency of MOPA are 2–3 times those of the simplex oscillator. It is found that the UV upconversion fiber MOPA system can effectively improve the output power and the slope efficiency of laser. [Copyright &y& Elsevier]

We report the first operation of a diode-side-pumped Nd:YVO4 laser in a bounce geometry at 1342 nm. Oscillator output power of 13.7 W in multimode is demonstrated with 38% slope efficiency and 10 W of single mode output with M2<1.1. A master oscillator power amplifier (MOPA) version of the bounce-geometry produces 20 W of output power. These results represent the highest power at 1342 nm from a Nd:YVO4 oscillator and oscillator-single-amplifier MOPA system. [Copyright &y& Elsevier]

Master oscillator power amplifier (MOPA) technology has been widely used in high-power or ultrashort-pulse fiber laser systems because the shape of the laser pulse can be easily adjusted. Usually, the first amplification stage of a 1064 nm fiber laser uses the core-pumped Yb-doped fiber amplifier (YDFA); however, the gain or output power is limited owing to the strong amplifier spontaneous emission (ASE) in the 1030 nm band. This paper presents the improved output power in an YDFA by inserting an additional unpumped Yb-doped fiber, which absorbs the lost backward ASE emitted from the pump end. We achieved an output power increase of more than 10% in a low-power signal, and the increase in output power decreased as the signal power increased. Moreover, the insertion of an additional unpumped Yb-doped fiber restricted the unwanted 1030 nm lasing in a low-power signal. [ABSTRACT FROM AUTHOR]