1016nm all fiber picosecond MOPA laser with 50W output

87-W 1018-nm Yb-fiber ultrafast seeding source for cryogenic Yb: yttrium lithium fluoride amplifier

We demonstrate a compact and robust Yb-fiber master-oscillator power-amplifier system operating at 1018 nm with 2.5-nm bandwidth and 1-ns stretched pulse duration. It produces 87-W average power and 4.9-μJ pulse energy, constituting a powerful seed source for cryogenically cooled ultrafast Yb: yttrium lithium fluoride (Yb:YLF) amplifiers.

High-power visible-enhanced all-fiber supercontinuum generation in a seven-core photonic crystal fiber pumped at 1016 nm

An 80 W 350-2400 nm monolithic supercontinuum (SC) source is reported. The high-power SC is generated in a uniform multi-core photonic crystal fiber (PCF) pumped by a 1016 nm pulsed fiber laser. The specially designed PCF has seven 4.5 μm diameter cores, a 0.85 air-filling fraction, and a zero dispersion wavelength (ZDW) of 991 nm. The 1016 nm pulsed laser delivers up to 114 W average power, which is believed to be the highest currently reported for picosecond fiber lasers working below 1020 nm. In order to ensure a robust and compact all-fiber structure, the pump laser is fusion spliced to the PCF using a selective air-hole collapse technique, achieving an ultra-low splicing loss of 0.2 dB despite the severe mode field mismatch. The proximity of the pump wavelength to the ZDW of PCF leads to enhanced visible generation. The output SC has a high spectral density of up to 108 mW/nm (at 580 nm) and over 50 mW/nm across the entire visible waveband. The achieved short-wavelength edge and high-spectral-power density in the visible region, to the best of our knowledge, are the best results reported for high-power visible SC sources.

Compact fs ytterbium fiber laser at 1010 nm for biomedical applications

Ytterbium-doped fiber lasers (YDFLs) working in the near-infrared (NIR) spectral window and capable of high-power operation are popular in recent years. They have been broadly used in a variety of scientific and industrial research areas, including light bullet generation, optical frequency comb formation, materials fabrication, free-space laser communication, and biomedical diagnostics as well. The growing interest in YDFLs has also been cultivated for the generation of high-power femtosecond (fs) pulses. Unfortunately, the operating wavelengths of fs YDFLs have mostly been confined to two spectral bands, i.e., 970-980 nm through the three-level energy transition and 1030-1100 nm through the quasi three-level energy transition, leading to a spectral gap (990-1020 nm) in between, which is attributed to an intrinsically weak gain in this wavelength range. Here we demonstrate a high-power mode-locked fs YDFL operating at 1010 nm, which is accomplished in a compact and cost-effective package. It exhibits superior performance in terms of both short-term and long-term stability, i.e., <0.3% (peak intensity over 2.4 μs) and <4.0% (average power over 24 hours), respectively. To illustrate the practical applications, it is subsequently employed as a versatile fs laser for high-quality nonlinear imaging of biological samples, including two-photon excited fluorescence microscopy of mouse kidney and brain sections, as well as polarization-sensitive second-harmonic generation microscopy of potato starch granules and mouse tail muscle. It is anticipated that these efforts will largely extend the capability of fs YDFLs which is continuously tunable over 970-1100 nm wavelength range for wideband hyperspectral operations, serving as a promising complement to the gold-standard Ti:sapphire fs lasers.

1018 nm Yb-doped high-power fiber laser pumped by broadband pump sources around 915 nm with output power above 100 W

We demonstrate a 1018 nm ytterbium-doped all-fiber laser pumped by tunable pump sources operating in the broad absorption spectrum around 915 nm. In the experiment, two different pump diodes were tested to pump over a wide spectrum ranging from 904 to 924 nm by altering the cooling temperature of the pump diodes. Across this so-called pump wavelength regime having a 20 nm wavelength span, the amplified stimulated emission (ASE) suppression of the resulting laser was generally around 35 dB, showing good suppression ratio. Comparisons to the conventional 976 nm-pumped 1018 nm ytterbium-doped fiber laser were also addressed in this study. Finally, we have tested this system for high power experimentation and obtained 67% maximum optical-to-optical efficiency at an approximately 110 W output power level. To the best of our knowledge, this is the first 1018 nm ytterbium-doped all-fiber laser pumped by tunable pump sources around 915 nm reported in detail.