High-power Yb-doped photonic bandgap fiber amplifier at 1150-1200 nm

Abstract

Ytterbium-doped solid-core photonic bandgap fiber amplifiers operating at the long-wavelength edge of the ytterbium gain band are reported. The low-loss bandgap transmission window is formed in the very low gain region, whilst outside the bandgap, large attenuation inhibits the exponential growth of amplified spontaneous emission in the huge-gain 1030-1100 nm region. Hence parasitic-lasing-free, high-power amplification with a marked efficiency is enabled. A 32 W output at 1156 nm with a 66% slope efficiency and 30 W output at 1178 nm with a 58% slope efficiency were successfully obtained. To our knowledge, these are the highest output powers generating from active photonic bandgap fibers, as well as from ytterbium-doped fiber lasers at these wavelengths.

Multi-watts narrow-linewidth all fiber Yb-doped laser operating at 1179 nm

“…Different approaches have been proposed to operate Yb-doped fiber lasers in the long wavelength (1160-1180 nm) range [4][5][6][7][8][9][10][11]. Because the emission cross-section of Yb-doped aluminosilicate fibre extends up to 1200 nm, using conventional Yb-doped fiber, an output of 121 mW at 1150 nm was achieved with a slope efficiency of 21%, by pumping at 977 nm [4].…”

“…Other alternatives have been proposed to overcome those issues, such as a cladding pumped Yb-doped solid photonic bandgap fibers for suppression of ASE at 1030 nm [8]. Also, by using the spectral filtering properties of photonic bandgap fibers, with a Raman fiber laser seeded MOPA configuration, 32 W output at 1156 nm and 30 W output at 1178 nm has been realized [10]. However, complex system structure and therefore difficult fabrication conditions with the additional possibility of photodarkening, when pumped at 915-976 nm; make such a laser impractical for industrial use.…”

Advances in Solid Core Photonic Bandgap Fiber Amplifiers

“…Yb-doped fibers have a very broad fluorescence spectrum extending up to 1200nm and the smallsignal gain per unit length can be as high as 0.8dB/m hence the net gain can easily exceed 10dB at 1178nm [7]. However, the large gain between 1030nm and 1100nm creates very strong ASE and can lead to parasitic lasing.…”

“…Furthermore, fiber amplifiers operating with built-in spectral gain shaping has recently emerged as a novel method for generating non-standard wavelengths such as 589nm by frequency doubling an 1178nm Yb-doped amplifier [7,8] or using cladding pumped Raman amplification. Both types of amplifiers require distributed spectral filtering to either suppress the ytterbium gain at lower wavelengths or to suppress the second Stokes wavelength to limit cascaded Raman processes [9].…”

Extending single mode performance of all-solid large-mode-area single trench fiber

“…That is why, this process dramatically increases the fabrication complexity. Moreover, these designs have their own problems such as PCF and H-PCF suffer from problem of cleaving and splicing of fibers due to presence of air holes [12], 2D-ASPBGF suffers from reduced cladding pump efficiency due to presence of high index Ge doped rods in cladding [13], and Bragg fiber suffers from unwanted coupling between core and ring modes due to imperfections in high index rings in realized fiber [14]. In addition to all these fibers, there have been several proposals of several fiber designs having additional layer or rings or tailored cladding around the core [15][16].…”