US-12620765-B2 - Counter-pumped fiber laser array system

Abstract

A fiber laser system includes: an array of gain fibers configured to transmit signal light; and an array of tapered end caps configured to receive the signal light and output the signal light, wherein each gain fiber in the array of gain fibers is spliced to a respective tapered end cap of the array of tapered end caps. A counter-pumping light source is configured to output counter-pumping light. A dichroic mirror is configured to receive the counter-pumping light and the signal light from the array of tapered end caps. The dichroic mirror is further configured to either allow the counter-pumping light received by the dichroic mirror to pass through the dichroic mirror and reflect the signal light received by the dichroic mirror or allow the signal light received by the dichroic mirror to pass through the dichroic mirror and reflect the counter-pumping light received by the dichroic mirror.

Inventors

• Donald Lee Sipes, JR.

Assignees

• OPTICAL ENGINES, INC.

Dates

Publication Date

20260505

Application Date

20210805

Claims (18)

1. 1 . A fiber laser system, comprising: an array of gain fibers configured to transmit signal light; an array of tapered end caps configured to receive the signal light from the array of gain fibers and output the signal light, wherein each gain fiber in the array of gain fibers is spliced to a respective tapered end cap of the array of tapered end caps; a counter-pumping light source configured to output counter-pumping light; and a dichroic mirror configured to receive the counter-pumping light from the counter-pumping light source and to receive the signal light from the array of tapered end caps, wherein the dichroic mirror is further configured to: allow the counter-pumping light received by the dichroic mirror to pass through the dichroic mirror and reflect the signal light received by the dichroic mirror; or allow the signal light received by the dichroic mirror to pass through the dichroic mirror and reflect the counter-pumping light received by the dichroic mirror; wherein the tapered end caps of the array of tapered end caps are tightly packed such that the array does not include any spaces between tapered end caps of the array; and wherein the counter-pumping light source is a single multi-element laser diode source configured to simultaneously output the counter-pumping light to the entire array of tapered end caps in parallel via the dichroic mirror.
2. 2 . The fiber laser system according to claim 1 , wherein each of the tapered end caps of the array of tapered end caps has a hexagonal shape.
3. 3 . The fiber laser system according to claim 1 , wherein each of the tapered end caps of the array of tapered end caps has a square shape.
4. 4 . The fiber laser system according to claim 1 , further comprising: a V-groove holder having a V-groove configured to hold the array of tapered end caps.
5. 5 . The fiber laser system according to claim 4 , wherein the V-groove comprises filler material around the array of tapered end caps held in the V-groove.
6. 6 . The fiber laser system according to claim 1 , further comprising: a plurality of variable-linewidth software-defined seed sources, each configured to output light pulses corresponding to the signal light.
7. 7 . The fiber laser system according to claim 6 , further comprising: a plurality of pre-amplifiers, each configured to receive light pulses from a respective variable-linewidth software-defined seed source and output amplified light pulses to a respective mode field adapter connected to a respective gain fiber of the array of gain fibers.
8. 8 . The fiber laser system according to claim 1 , further comprising: a shaping and imaging optics assembly configured to receive the counter-pumping light and focus the counter-pumping light towards the array of tapered end caps.
9. 9 . A fiber laser system, comprising: an array of gain fibers configured to transmit signal light; and an array of tapered end caps configured to receive the signal light from the array of gain fibers and output the signal light, wherein each gain fiber in the array of gain fibers is spliced to a respective tapered end cap of the array of tapered end caps; wherein the tapered end caps of the array of tapered end caps are tightly packed such that the array does not include any spaces between tapered end caps of the array; and wherein the entire array of tapered end caps is configured to be simultaneously counter-pumped in parallel via a dichroic mirror by a single multi-element laser diode source configured to output counter-pumping light to the array of tapered end caps.
10. 10 . The fiber laser system according to claim 9 , wherein each of the tapered end caps of the array of tapered end caps has a hexagonal shape.
11. 11 . The fiber laser system according to claim 9 , wherein each of the tapered end caps of the array of tapered end caps has a square shape.
12. 12 . The fiber laser system according to claim 9 , further comprising: a plurality of variable-linewidth software-defined seed sources, each configured to output light pulses corresponding to the signal light.
13. 13 . The fiber laser system according to claim 9 , further comprising: a plurality of pre-amplifiers, each configured to receive light pulses from a respective variable-linewidth software-defined seed source and output amplified light pulses to a respective mode field adapter connected to a respective gain fiber of the array of gain fibers.
14. 14 . The fiber laser system according to claim 9 , further comprising: a polarizer configured to receive the signal light output from the array of tapered end caps and to separate the received signal light into two orthogonal polarizations; and a second harmonic generation (SHG) unit configured to receive the two orthogonal polarizations and recombine them to form an output beam of the fiber laser system.
15. 15 . The fiber laser system according to claim 14 , wherein each of the tapered end caps of the array of tapered end caps has a hexagonal shape.
16. 16 . The fiber laser system according to claim 14 , wherein each of the tapered end caps of the array of tapered end caps has a square shape.
17. 17 . The fiber laser system according to claim 14 , wherein the SHG unit is further configured to utilize a frequency doubling scheme in heated lithium triborate (LBO) crystals or barium borate (BBO) crystals.
18. 18 . The fiber laser system according to claim 14 , further comprising: a plurality of variable-linewidth software-defined seed sources, each configured to output light pulses; and a plurality of pre-amplifiers, each configured to receive light pulses from a respective variable-linewidth software-defined seed source and output amplified light pulses to a respective mode field adapter connected to a respective gain fiber of the array of gain fibers.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Patent Application No. 63/061,393, filed on Aug. 5, 2020, which is incorporated by reference herein in its entirety. BACKGROUND Fiber lasers are becoming increasingly deployed in industrial, scientific, medical, and defense applications due to their high efficiency, robust and reliable construction, and relatively low system size and weight. There is considerable interest, for example, in the potential of using laser light for creating high intensity fiber laser sources for inertial fusion applications. While bulk solid-state lasers can provide the required high pulse energies, thermal effects limit their use to <10 Hz. Fiber lasers, on the other hand, can provide higher average power levels to the multi-kW level and better beam qualities, but are limited in pulse energy due to the onset of fiber nonlinearities. Coherently combined fiber laser arrays where a single seed source is split many ways and directed into a parallel array of fiber amplifiers and then coherently combined into the far field either in a tiled configuration, a mirror structure, or a diffractive optical element are promising. However, even lower power high energy density laboratory plasma (HELDP) applications may require hundreds, even thousands of individual fiber lasers. Further, conventional fiber laser arrays are very complex, requiring individual pump lasers, combiners and mode adapters for each channel. SUMMARY In an exemplary embodiment, the present disclosure provides a fiber laser system. The fiber laser system includes: an array of gain fibers configured to transmit signal light; an array of tapered end caps configured to receive the signal light from the array of gain fibers and output the signal light, wherein each gain fiber in the array of gain fibers is spliced to a respective tapered end cap of the array of tapered end caps. A counter-pumping light source is configured to output counter-pumping light. A dichroic mirror is configured to receive the counter-pumping light from the counter-pumping light source and to receive the signal light from the array of tapered end caps. The dichroic mirror is further configured to allow the counter-pumping light received by the dichroic mirror to pass through the dichroic mirror and reflect the signal light received by the dichroic mirror or allow the signal light received by the dichroic mirror to pass through the dichroic mirror and reflect the counter-pumping light received by the dichroic mirror. In a further exemplary embodiment, each of the tapered end caps of the array of tapered end caps has a hexagonal shape. In a further exemplary embodiment, each of the tapered end caps or the array of tapered end caps has a square shape. In a further exemplary embodiment, the tapered end caps of the array of tapered end caps are tightly packed such that adjacent tapered end caps do not have space between them. In a further exemplary embodiment, the fiber laser system further includes a V-groove holder having a V-groove configured to hold the array of tapered end caps. In a further exemplary embodiment, the V-groove comprises filler material around the array of tapered end caps held in the V-groove. In a further exemplary embodiment, the fiber laser system further includes a plurality of pre-amplifiers, each configured to receive light pulses from a respective variable-linewidth software-defined seed source and output amplified light pulses to a respective mode field adapter connected to a respective gain fiber of the array of gain fibers. In a further exemplary embodiment, the counter-pumping light source is a multi-element laser diode source. In a further exemplary embodiment, the fiber laser system further includes a shaping and imaging optics assembly configured to receive the counter-pumping light and focus the counter-pumping light towards the array of tapered end caps. In another exemplary embodiment, the present disclosure provides a fiber laser system. The fiber laser system includes: an array of gain fibers configured to transmit signal light; an array of tapered end caps configured to receive the signal light from the array of gain fibers and output the signal light, wherein each gain fiber in the array of gain fibers is spliced to a respective tapered end cap of the array of tapered end caps. The tapered end caps of the array of tapered end caps are tightly packed such that adjacent tapered end caps do not have space between them. In a further exemplary embodiment, each of the tapered end caps of the array of tapered end caps has a hexagonal shape. In a further exemplary embodiment, each of the tapered end caps of the array of tapered end caps has a square shape. In a further exemplary embodiment, the fiber laser system further includes a plurality of variable-linewidth software-defined seed sources, each configured to output light pulses corresponding to the signal light. In a further exemplary e