06-32 μm supercontinuum generation in a step-index germania-core fiber using a 44 kW peak-power pump laser

Abstract

An ultra-broadband supercontinuum was generated in a short piece of step-index germania-core fiber using a fiber laser with a peak power of 4.4 kW. The pure germania core made this fiber capable of propagating light towards the desirable mid-infrared region. The spectral broadening characteristics towards the mid-infrared region under different lengths of germania-core fiber were investigated using pump pulses of 4.4 kW and 1.1 ns at 1550 nm. The large nonlinear refractive index of germania and the small core size of germania-core fiber produced a nonlinear coefficient as high as 11.8 (W km)^-1 at 1550 nm, which was beneficial for supercontinuum generation. The pump wavelength was located in the anomalous dispersion regime and close to the zero dispersion wavelength of this germania-core fiber, 1.426 μm. Eventually, an ultra-broadband supercontinuum source with a spectrum spanning from 0.6 to 3.2 μm was obtained and had a total output power of 350 mW at an optimized germania-core fiber length of 0.8 m. This work is the first demonstration, to the best of our knowledge, of a germania-core fiber-based ultra-broadband supercontinuum source that spans from the visible region to the mid-infrared region.

Record power, ultra-broadband supercontinuum source based on highly GeO_2 doped silica fiber

“…A pump source near 1550 nm has led to spectral broadening towards visible wavelength, on the contrary a pump source near 2000 nm limits broadening towards blue wavelength to 1700 nm [15,[17][18][19]. The measured ZDW of GeO 2 glass is around 1.73-1.74 μm, however for a GeO 2 doped fiber, the ZDW will depend on the exact concentration of GeO 2 (as it decides NA of fiber as well) and core diameter.…”

“…In this experiment, a pure GeO 2 doped fiber with 9 μm core diameter was used and the obtained spectrum suffered from a broad OH absorption peak around 2700 nm. In 2016 Yang et al demonstrated an SC with a 10dB bandwidth of 717 nm to 2998 nm, with a total of 450 mW output power [19]. A pure GeO 2 core fiber of 3 μm core diameter was used.…”

Near Infrared Supercontinuum Generation in Silica Based Photonic Crystal Fiber

“…Various supercontinuum (SC) generated highly nonlinear photonic crystal fibers (HN-PCFs) have been reported in the literature for optical communications and medical applications [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], using different materials to produce broadband SC spectrum with varying performances.…”

“…Different designs of femtosecond (fs), picosecend and nanosecond pulse laser sources are proposed and consequently, investigated in references [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. In [10], the authors investigate the performance of femtosecond-laser pulses in neodymium-doped yttrium aluminium garnet (Nd:YAG) crystals and report that output power of around 1.3 W at around 1.0 µm center wavelength is achievable from an 2.25 W launched pump power.…”

High power, ultra-broadband supercontinuum source based on highly GeO2 doped silica fiber

“…Initial attempts of SC generation in highly doped GeO 2 fiber involve a 2 μm laser as a pump source, which limits the blue edge of the spectrum above 1.7 μm [2]. Recently, Yang et al claimed a pure Germania core fiber with a 1.426 μm ZDW and demonstrated a 10 dB bandwidth from 717 nm to 2998 nm but output power was limited to 350 mW [3]. In this paper, we report a SC based on a 74 mol % GeO 2 doped core fiber, which is being pumped by a broadband 4-stage Er-Yb fiber based master oscillator power amplifier (MOPA).…”