Yb-doped Master Oscillator Power Amplifier Research Articles

1.5-kW all-fiberized Yb-doped MOPA laser at 1105 nm with near-diffraction-limited beam quality and narrow spectral width

We demonstrate an all-fiberized ytterbium-doped fiber laser (YDFL) at 1104.9 nm with a high optical signal-to-noise ratio (OSNR) by using ytterbium gain purely. The system is built based on FBG-based master oscillator power amplifier (MOPA) configuration, producing 1.5-kW power with a near-diffraction-limited beam quality (M2∼1.4) and a narrow spectral linewidth (FWHM∼70 GHz). The OSNR is ∼33 dB. A theoretical model is developed to calculate the amplified spontaneous emission (ASE) in the final amplifier. Both the calculated and experimental results suggest that the ASE or even parasitic lasing is the primary limitation for further power scaling. To the best of our knowledge, in >1100 nm wavelength range, this is the highest output power narrow spectral YDFL (with <100 GHz 3-dB spectral width) by using FBG-based MOPA configuration.

Hundred-watt level linearly polarized visible supercontinuum generation.

An all-fiber linearly polarized supercontinuum (SC) laser source with 93 W average output power and spectrum ranging from 520 nm to 2300 nm is experimentally demonstrated. The linearly-polarized SC is generated in a piece of 2.6 m long polarization-maintaining photonic crystal fiber (PM-PCF), pumped by a polarization-maintaining picosecond Yb-doped master oscillator power amplifier (PM-MOPA). The source exhibits a flat spectrum from 600 nm to 1880 nm at -10 dB level except for the residual pump peak. A new method is proposed to measure the polarization extinction ratio (PER) of each single wavelength of the broadband supercontinuum at a high-power level, resulting in larger than 16 dB PER from 900 nm to 1600 nm and larger than 15 dB PER from 540 nm to 650 nm. To our knowledge, this is the first demonstration of hundred-watt level linearly polarized visible SC and the first demonstration of PER measurement of each single wavelength within such a wide spectrum range.

Ultraviolet-enhanced supercontinuum generation with a mode-locked Yb-doped fiber laser operating in dissipative-soliton-resonance region.

We experimentally demonstrate an all-fiber, ultraviolet-enhanced, supercontinuum generation in a specifically designed seven-core photonic crystal fiber pumped by a picosecond Yb-doped master oscillator power amplifier (MOPA). The MOPA source is seeded by a giant-chirped Yb-doped mode-locked fiber laser operating in the dissipative-soliton-resonance (DSR) region. The DSR is achieved by using a nonlinear optical loop mirror (NOLM) with a fundamental repetition rate of 4.5 MHz and a central wavelength of 1035 nm. An extremely wide optical spectrum spanning from 350 nm to 2400 nm is obtained with a total output power of 6.86 W.

An All-Fiber Supercontinuum Source With 30.6-W High-Power and Ultrawide Spectrum Ranging From 385 nm to Beyond 2400 nm

An all-fiber high power, blue-enhanced supercontinuum generation in a piece of uniform photonic crystal fiber pumped by a picosecond Yb-doped master oscillator power amplifier (MOPA) is experimentally demonstrated. The MOPA source is seeded by an actively dissipative soliton mode-locked Yb-doped fiber laser with a fundamental repetition rate of approximately 15.33 MHz and a large chirp. By introducing giant chirp to the seed pulses and optimizing the pump power in every stage of the MOPA, an SC with 30.6-W output average power and an extremely wide spectrum of 385 nm to beyond 2400 nm is obtained.