Study of dopant concentrations on thermally induced mode instability in high-power fiber amplifiers

Tao, Rumao; Ma, Pengfei; Wang, Xiaolin; Zhang, Pu; Liu, Zejin

doi:10.1088/1054-660x/26/6/065103

Cited by 14 publications

(11 citation statements)

References 53 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Interestingly, the larger core size makes the frequency offset difference before and after PD saturation smaller because the mode profile becomes flatter and produces similar inversion profile. This observation agrees with the results in [124].…”

Section: Core Radiussupporting

confidence: 94%

“…As discussed, the threshold power remains nearly same at 415 W at the investigated concentrations in the fibres before PD. This is in consistent with the experimental result presented in [124]. However, the threshold power continuously decreases from 405 W to 315 W, with increasing ion concentration from 0.5×10 25 m -3 to 3.5×10 25 m -3 as deduced from Eq.…”

Section: Core Radiussupporting

confidence: 92%

“…It was already pointed out that reducing ion concentration is effective to suppress the TMI [73]. On the other hand, it was also reported that TMI thresholds are independent of ion concentration [124] when the PD is absent. Hence, it becomes interesting to understand the thermal load contribution from the QD and PD, accounting for the TMI.…”

Section: Core Radiusmentioning

confidence: 98%

See 2 more Smart Citations

Investigation of transverse mode instability suppression in large mode area fibre

Xia¹

View full text Add to dashboard Cite

In the past decades, fibre laser and amplifier systems have seen a rapid power increase due to the efficient heat dissipation and robust single-mode operation. The fibre lasers and amplifiers have become attractive sources for applications spanning from industry and defence to scientific research. In particular, the fibre lasers and amplifiers have penetrated for material processing industry including marking, cutting, welding and drilling. It had been known that the highest achievable output power in fibre laser and amplifier systems is largely limited by the nonlinear scatterings such as stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS). However, a new phenomenon under high power operation, the so-called transverse mode instability (TMI), was experimentally observed in a large mode area (LMA) ytterbium (Yb)-doped fibre amplifier in 2011. The TMI can occur much earlier than the SBS and SRS in average power scaling, hence becoming the first limitation in high-power fibre operations till now. The TMI refers to the output beam degradation, caused by the power transfer from the fundamental mode (FM) to the higher-order mode (HOM), for input pump power above a certain threshold. The origin of TMI is attributed to the stimulated thermal Rayleigh scattering x

show abstract

Section: Core Radiussupporting

confidence: 94%

Section: Core Radiussupporting

confidence: 92%

See 1 more Smart Citation

Investigation of transverse mode instability suppression in large mode area fibre

Xia¹

View full text Add to dashboard Cite

show abstract

“…The PD-measured time traces have been recorded by detecting the scattering light from the power meter, which agree well with those sampled the small spatial portion of low-power beam profile directly [12], and has been employed in Ref. [13] and [14]. Beam quality (M 2 ) was measured by a M 2 meter with the D4σ definition [15], and the typical accuracy of M 2 meter is less than ±5%.…”

Section: Methodsmentioning

confidence: 80%

SRS-Induced Spatial-Spectral Distortion and Its Mitigation Strategy in High-Power Fiber Amplifiers

Zhang

Xie

et al. 2022

IEEE Photonics J.

Self Cite

View full text Add to dashboard Cite

The spatial-spectral evolution properties of laser beam in the presence of stimulated Raman scattering (SRS) effect have been studied in large mode area (LMA) fiber. With the employment of long/short pass filters, spatial evolution of the signal and Raman light has been studied individually. After the onset of SRS, the simultaneous optimizing of signal light and degrading of Raman light was observed, which has been attributed to the SRS effect of multimode laser beams in LMA fiber. The spectral evolution characteristics indicated that the SRS effect in LMA fiber will trigger other nonlinear effects, mainly inter-modal four-wave-mixing effect and cross-phase-modulation induced modulation instability. Furthermore, the impacts of bending strategy and multimode LMA fiber on SRS-induced spatialspectral distortion have also been studied, which shows that the SRS-induced mode distortion can be suppressed by increasing the fiber size while the bending strategy plays a limited role.

show abstract

“…This is due to that the pump and signal power distributions are the same for these conditions, which result to that the population inversion or hole burning effects are the same in the two cases. While other factors that have impact on mode instability remain untouched, the mode instability threshold is constant [56,57]. This is important for numerical calculation, which means that the length of the fiber can be shortened to save the calculation time by suitably choosing the dopant concentration and the averaged coupling coefficient.…”

Section: Dynamic Mode Instability In One-pump-core Dsccp Fiber Amplifiersmentioning

confidence: 99%

Static and dynamic mode evolution in high-power distributed side-coupled cladding-pumped fiber amplifiers

Tao

Liu

Xie

et al. 2021

High Pow Laser Sci Eng

Self Cite

View full text Add to dashboard Cite

We present a theoretical study of mode evolution in high power distributed sidecoupled cladding-pumped (DSCCP) fiber amplifiers. A semi-analytical model taking the side pumping schemes, transverse mode competition and stimulated thermal Rayleigh scattering into consideration has been built, which can model the static and dynamic mode evolution in high power DSCCP fiber amplifiers. The mode evolution behavior has been investigated with variation of fiber amplifier parameters, such as the pump power distribution, the length of the DSCCP fiber, the averaged coupling coefficient, the number of the pump cores, and the arrangement of pump cores. Interestingly, it revealed that static mode evolution induced by transverse mode competition is different from the dynamic ones induced by stimulated thermal Rayleigh scattering. It shows that the high order mode experiences slightly higher gain in DSCCP fiber amplifiers, but the mode instability thresholds for DSCCP fiber amplifiers are higher than those end-coupled counterparts. By increasing the pump core number and reducing the averaged coupling coefficient, the mode instability threshold can be increased, which

show abstract

Study of dopant concentrations on thermally induced mode instability in high-power fiber amplifiers

Cited by 14 publications

References 53 publications

Investigation of transverse mode instability suppression in large mode area fibre

Investigation of transverse mode instability suppression in large mode area fibre

SRS-Induced Spatial-Spectral Distortion and Its Mitigation Strategy in High-Power Fiber Amplifiers

Static and dynamic mode evolution in high-power distributed side-coupled cladding-pumped fiber amplifiers

Contact Info

Product

Resources

About