550 W single frequency fiber amplifiers emitting at 1030 nm based on a tapered Yb-doped fiber

Abstract

In this paper, we report a high power single frequency 1030 nm fiber laser with near-diffraction-limited beam quality based on a polarization-maintaining tapered Yb-doped fiber (T-YDF). The T-YDF has advantages of effectively suppressing stimulated Brillouin scattering (SBS) while maintaining good beam quality. As a result, a record output power of 379 W single frequency, linearly polarized, nearly single-mode fiber amplifier operating at 1030 nm is demonstrated. The polarization extinction ratio is as high as 16.3 dB, and the M2 is measured to be 1.12. Further, the dependence of the thermal-induced mode instability (TMI) threshold on the polarization state of an input signal laser is investigated for the first time. By changing the polarization state of the injected seed laser, the output power can increase to 550 W while the beam quality can be maintained well (M2=1.47). The slope efficiency of the whole amplifier is about 80%. No sign of SBS appears even at the highest output power and the further brightness scaling of both situations is limited by the TMI effect. To the best of our knowledge, this result is the highest output power of all-fiberized single frequency fiber amplifiers.

High‐Power Laser Systems

“…At present, it has been adopted in kW-level allfiber resonators, [410] MOPA amplifiers, [411] MW-level CPA-free amplification, [409,412] and high-power single-frequency (SF) laser output. [413,414] Filippov et al manufactured and systematically studied the critical parameters of tapered fiber both theoretically and experimentally. [406,415] By optimizing the taper ratio, longitudinal profile, pump absorption coefficient, and core/cladding diameter ratio, the vignetting loss has been reduced to 0.45%.…”

“…The power scaling was limited by the TMI. [414] 3.5. PCF PCF, as a kind of microstructure fiber usually made of a single material, is distinguished by the periodic air-hole array running along the whole length of the fiber.…”

“…At present, it has been adopted in kW‐level all‐fiber resonators, [ 410 ] MOPA amplifiers, [ 411 ] MW‐level CPA‐free amplification, [ 409,412 ] and high‐power single‐frequency (SF) laser output. [ 413,414 ]…”

High Power Narrow-Linewidth Fiber Lasers

“…High power narrow-linewidth fiber lasers have been under intensive investigation due to their potential applications in beam combination (coherent and spectral), gravitational wave detection (GVD), nonlinear frequency conversion and so on. In this talk, we will present the progress of high power narrow-linewidth fiber lasers in our lab [1][2][3][4][5][6][7][8][9] in the past few years and the very recent result.…”

“…Because of the newly discovered transverse modal instability (TMI) effect, further power scaling is limited by both SBS and TMI effects. Recently, by using polarizationmaintaining tapered Yb-doped fiber (T-YDF) and shorter seed wavelength, SBS and TMI can be well suppressed simultaneously, a 550 W single frequency fiber MOPA has been achieved with a slope efficiency of 80% [3].…”