Self-frequency-shifted solitons in a polarization-maintaining, very-large-mode area, Er-doped fiber amplifier

Abstract

We demonstrate soliton self-frequency-shifted, femtosecond-pulse amplification in a newly-developed, polarization-maintaining, Er-doped, very-large-mode-area fiber amplifier. The PM-VLMA Er fiber had a core diameter of 50 μm, an effective area of ~1050 μm², and Er absorption of 50 dB/m. The measured birefringence beat length of the PM-VLMA Er fiber was 14.1 mm. The soliton wavelength could be shifted by more than 90 nm. The soliton generation process resulted in remarkably clean, 86 fs pulses with 21 nJ energy at 1650 nm and 244 kW peak power from an all-fiber, fusion spliced system without bulk-optics for pulse compression. The polarization extinction ratio of the soliton was greater than 40 dB, and the M² was 1.1. The fully polarization-maintaining fiber laser system provides robust and stable soliton generation. Peak-to-peak variation in the soliton wavelength, measured over the course of an hour was only 0.03% and pulse energy variation was only 0.5%.

Spatiotemporal Mode-Locking in Lasers with Large Modal Dispersion

“…The various nonlinear spatiotemporal dynamics in passive graded-index (GRIN) MMFs have been investigated extensively in recent years, including studies of spatiotemporal instability [4][5][6], spatial beam cleaning [7][8][9][10][11][12], supercontinuum generation [12][13][14][15][16][17], and control of nonlinear multimode interactions [18,19]. In addition, nonlinear pulse propagation in amplifiers composed of active MMFs was studied [20][21][22][23]. However, very little work on MMF cavities with multimode nonlinear dynamics has been performed.…”

Nonlinear chirped pulse amplification for a 100-W-class GHz femtosecond all-fiber laser system at 1.5 m

“…Frontier applications, however, have a high demand for HPFFLs at 1.5 m, for example, high-aspect-ratio through-silicon-vias fabrication [ 11 ] and corneal surgery [ 12 , 13 ] . Moreover, HPFFLs at 1.5 m are promising drive sources for frequency conversions through second-harmonic generation [ 14 , 15 ] , Cherenkov radiation [ 16 ] , soliton self-frequency shift (SSFS) [ 17 , 18 ] and self-phase modulation [ 19 ] , to name just a few. In general, the average-power (or pulse-energy) scaling of the 1.5- m fs fiber laser is mainly based on chirped pulse amplification (CPA) [ 20 ] .…”

All-fiber high-power 1700 nm femtosecond laser based on optical parametric chirped-pulse amplification

“…To get around this, large-mode-area fibers are usually used for high-power soliton lasers [9,10], but they sacrifice the robustness of the fiber format due to the free-space optics needed for fiber-coupling or pre-compression of pump pulses. Recently, an all-fiber Raman soliton working at 1680 nm with 1.6 W average output power has been demonstrated [11], which utilized a specially designed Er-doped very-large-mode-area (VLMA) fiber by OFS [12]. Because this Er-doped VLMA can tolerate much higher peak power during the high-power amplification process, the output can be directly spliced to another VLMA to generate Raman soliton without the use of free-space optics for fiber-coupling.…”