Pump-gain integrated functional laser fiber towards 10 kW-level high-power applications

Abstract

To incorporate sufficient pump energy from multi-hundred watt-level 976 nm commercial laser diodes, a new kind of (8 + 1)-type pump-gain integrated functional laser ((8 + 1)-PIFL) fiber was fabricated by our newly optimized special fiber assembly and coating techniques for the first time. This (8 + 1)-PIFL fiber allowed for 10.66 kW aggregated pump power at 976 nm from six counter-pump ports in a master oscillator power amplifier laser setup and stably presented 8.72 kW laser output at 1079.4 nm with a high optical-to-optical efficiency of 81.0%. This is the highest power of the fiber amplifiers pumped by commercial laser diodes that has been reported so far, and only limited by the available pump power. Up to this power level, pure output spectrum with narrow 3 dB bandwidth Δλ3 dB of 2.76 nm and without any sign of stimulated Raman scattering and amplified spontaneous emission was obtained. Neither roll over of output power nor obvious thermal issue was observed with increased pump power, indirectly justifying strong photodarkening and transverse mode instability suppression. With another ten pump ports to collect more pump power, a further power scaling towards 10 kW or above can be expected.

Ultra high power fiber laser employing homemade (1+1) side-pumped fiber and tandem-pumping technique

“…In this case, if more pumping power are expected to inject, one just need to simply increase the number of pump cores. With LD pumping source, the reported maximum output power of all-fiberized LDSP is 11.23 kW [12][13][14][15]. The situation is rather complicated when considering a higher power up to 20 or 30 kW.…”

Industrial 6 kW high-stability single-stage all-fiber laser oscillator based on conventional large mode area ytterbium-doped fiber

“…During the past two decades, owing to the rapid development of high-brightness laser diodes (LDs) and the large mode area (LMA) double-cladding fiber fabrication technology, the average output power of fiber lasers has experienced a dramatic boost with near diffraction-limited beam quality [3][4][5]. At present, a number of high-power continuouswave (CW) fiber lasers with output power beyond 5 kW are realized through a master oscillator power amplifier (MOPA) architecture [6][7][8][9][10]. However, the MOPA system is susceptible to reflection from materials during processing, which makes it restricted in industrial applications.…”

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

“…Due to the far-reaching impact, mode instability in various fiber laser systems has been under extensive theoretical and experimental investigation in recent years, but most of the work belongs to fiber lasers employing end-coupled cladding-pumping (ECCP) schemes [8,9]. Sidepumping scheme, especially distributed side-coupled cladding-pumped (DSCCP) fiber or GTWave fiber, is another good choice for high power fiber laser systems [13][14][15][16][17], which is one of the important technologies to enable high power scaling of fiber lasers [18][19][20][21][22][23][24]. Impressing power results have been reported in [17,22], where signal fiber with large pump area and backward pumping scheme has been employed to suppress mode instability [17].…”

“…Sidepumping scheme, especially distributed side-coupled cladding-pumped (DSCCP) fiber or GTWave fiber, is another good choice for high power fiber laser systems [13][14][15][16][17], which is one of the important technologies to enable high power scaling of fiber lasers [18][19][20][21][22][23][24]. Impressing power results have been reported in [17,22], where signal fiber with large pump area and backward pumping scheme has been employed to suppress mode instability [17]. Recently, researchers have reported mode instability in DSCCP lasers [25,26].…”

“…Impressive power results have been reported in Refs. [17,22], where signal fiber with a large pump area and backward pumping scheme was employed to suppress mode instability [17] . Recently, researchers have reported mode instability in DSCCP lasers [25,26] .…”