High power ytterbium-doped rod-type three-level photonic crystal fiber laser

Abstract

In this paper, we investigate power scalability of ytterbium-doped ultra large core photonic crystal fiber laser operating on the zero-line transition. We first report on an 80 microm core diameter ytterbium-doped rod-type photonic crystal fiber laser emitting up to 94 W in continuous wave regime when operating at 977 nm, which is to our knowledge the highest output power ever achieved from a single-mode solid-state laser operating at this wavelength. Key parameters of ytterbium-doped three-level laser, such as transparency pump intensity, pump absorption saturation, and gain competition between three and four-level laser operation are then discussed in the particular context of high power fiber laser operating at 977 nm.

Yb Fiber Amplifier at 972.5 nm with Frequency Quadrupling to 243.1 nm

“…It appears that our fiber amplifier platform should be able to produce additional 972 nm radiation through either more powerful, commercially available pump diodes or with an additional fiber amplifier stage of similar design [25]. To use the 915 nm pump radiation more efficiently would require that we obtain fibers with a larger core/cladding area ratio, such as the rod-type fibers used in [17,18]. The doubling stages were designed with relatively loose focusing in the crystals.…”

“…Gain near the emission cross section peak at 976 nm is also possible but requires population inversions above ∼50% because the absorption cross section in that spectral region has approximately the same magnitude. Despite this difficulty, there have been demonstrations of 100 W Yb doped fiber lasers near arXiv:1607.06574v2 [physics.atom-ph] 25 Jul 2016 the emission cross section peak at 976 nm [17,18]. To the best of our knowledge, there have been only a few Yb fiber-based laser systems which operate at shorter wavelengths and these produced relatively low power (∼ 10 mW) [19,20].…”

Development of high-energy fiber CPA system

“…The pump source of the LMA fiber was a fibercoupled quasi-continuous-wave (QCW) LD with a maximum power of 30 W at a 975-nm wavelength. The main amplifier was constructed using a polarization-maintaining, air-clad, photonic-crystal, rodtype fiber with a core diameter of 100 m (DC-285-100-PM-Yb-ROD, NKT Photonics) [4,11] pumped by a fiber-coupled QCW LD with a maximum power of 100 W. To reduce the thermal effects in the LMA and rod fibers, the LD pumping was operated at a repetition rate of 10 kHz with a 50% duty cycle.…”

Compact fs ytterbium fiber laser at 1010 nm for biomedical applications

“…Excellent performance characteristics of continuous wave (CW), nanosecond (ns), picosecond (ps) and femtosecond (fs) YDFLs have been intensively demonstrated so far [8][9][10]. Therein, the working wavelength of YDFLs has long been limited to two typical spectral bands: 970-980 nm which exploits three-level transition and 1030-1100 nm which is dominated by quasi-three-level transition [11][12][13][14]. However, YDFLs working at 990-1020 nm have rarely been demonstrated, mainly due to the small gain coefficient and the gain competition from the three-level and quasi-three-level bands [1].…”