56-W Frequency-Doubled Source at 530 nm Pumped by a Single-Mode, Single-Polarization, Picosecond, Yb$^{3+}$-Doped Fiber MOPA

Abstract

Abstract-We report a frequency doubled green source at 530nm pumped based on an all-fiber, picosecond, single polarization Yb 3+-doped fiber MOPA delivering 20ps pulses at user selectable repetition rates of up to 910MHz and an average output power in excess of 100W at 1.06µm. The output of the MOPA was frequency doubled using a LBO crystal. Up to 56 W of green light was generated at a corresponding repetition rate of 227 MHz at an overall conversion efficiency of 56%. The diodeto-green optical power conversion efficiency was 37%.

High-Peak-Power Tunable Source at 550 nm From a Frequency-Doubled Yb-Doped Fiber MOPA

“…The length optimization of the gain fiber is critical for long wavelength operation. Different optimized lengths for different signal wavelengths have been reported using the same type of fiber, such as 0.85 m long fiber for λ~1034 nm [18] and 3 m long fiber for λ~1060 nm [14]. For the first preamplifier, we measured the forward ASE spectrum at different active fiber lengths but with the same pump power of 300 mW.…”

“…Additionally, by means of external cavity frequency conversion techniques, the spectral coverage of YDFAs can be extended to the visible range with similar advantages. A nonlinear crystal, such as lithium triborate (LBO) [14], β−Barium borate (BBO) [15] or a periodically poled nonlinear crystal [16], is normally employed in the single-pass configuration for second harmonic generation (SHG). However, frequency-doubled, high-power tunable pulsed green lasers operating around λ~550 nm have rarely been reported to date.…”

Generation of 110 W infrared and 65 W green power from a 13-GHz sub-picosecond fiber amplifier

“…An achromatic doublet (AC254-075-B, f = 7.5 cm) from Thorlabs is used to focus the amplifier beam to a 50-micron diameter. The crystal is cut for the commonly-used type-I temperature-tuned interaction [11,17]. With increasing input, it is necessary to adjust the oven temperature to compensate for the internal heating of the LBO crystal [18].…”

“…The repetition rate of pulsed fiber amplifiers is typically less than 200 MHz. There are a few recent reports of high-power fiber laser systems with higher repetition rates [9][10][11][12][13]. These systems are seeded by pulses in the range of 5-20 ps.…”

Generation of 167 W infrared and 124 W green power from a 13-GHz, 1-ps rod fiber amplifier

“…Fiber lasers are an excellent choice as they can deliver high average power with high slope efficiency and diffraction-limited beam quality [4,5]. High-power pump light can be efficiently coupled into the large-mode area, double-clad gain fibers, delivering IR ps pulses with more than 100 W average power [6][7][8][9][10][11][12][13][14][15], and green ps pulses through second harmonic generation (SHG) [10][11][12]15]. Also, the diffraction-limited beam quality can be reliably maintained in the very high-power regime due to the outstanding thermo-optical properties and the waveguide structure in the double-clad fibers.…”