1.9-3.6  μm supercontinuum generation in a very short highly nonlinear germania fiber with a high mid-infrared power ratio.

In this Letter, a high-power supercontinuum (SC) laser source which spanned from 1.9 to 3.6 μm with an all-fiber configuration was reported. This SC laser was obtained by concatenating a thulium-doped fiber amplifier (TDFA) and a 12 cm long highly nonlinear germania fiber. A 1.9-2.7 μm SC laser from the TDFA was spectrally broadened continuously into the mid-infrared region (>3  μm) in the following germania fiber. When the repetition rate was 2 MHz, the obtained SC laser had a maximum output power of 6.12 W with an optical conversion efficiency of 15.3% with respect to the TDFA pump power. The SC laser had a spectral bandwidth of 1506 nm ranging from 1944 to 3450 nm at the -20  dB level. The SC power with wavelengths >3  μm was 2.9 W, corresponding to a high power ratio of 47.4% in the mid-infrared region. The achieved power ratio in the mid-infrared region, as well as the long wavelength cutoff, to the best of our knowledge, were the best results ever reported in germania fibers.

[1]  J. Świderski,et al.  Mid-infrared supercontinuum generation in a single-mode thulium-doped fiber amplifier , 2013 .

[2]  T. Kato,et al.  Estimation of nonlinear refractive index in various silica-based glasses for optical fibers. , 1995, Optics letters.

[3]  Ke Yin,et al.  Over an octave cascaded Raman scattering in short highly germanium-doped silica fiber. , 2013, Optics express.

[4]  V. Mashinsky,et al.  Generating tunable optical pulses over the ultrabroad range of 1.6-2.5 μm in GeO2-doped silica fibers with an Er:fiber laser source. , 2012, Optics express.

[5]  J. Hou,et al.  0.6-3.2 μm supercontinuum generation in a step-index germania-core fiber using a 4.4 kW peak-power pump laser. , 2016, Optics express.

[6]  S. Dai,et al.  Ultrabroad supercontinuum generated from a highly nonlinear Ge-Sb-Se fiber. , 2016, Optics letters.

[7]  H. H. Chen,et al.  Ultraviolet-extended flat supercontinuum generation in cascaded photonic crystal fiber tapers , 2013 .

[8]  A. Andrianov,et al.  Towards Mid-Infrared Supercontinuum Generation With Germano-Silicate Fibers , 2014, IEEE Journal of Selected Topics in Quantum Electronics.

[9]  Yuri Yatsenko,et al.  D-scan measurement of nonlinear refractive index in fibers heavily doped with GeO2. , 2007, Optics letters.

[10]  Mohammed N. Islam,et al.  Modulation instability initiated high power all-fiber supercontinuum lasers and their applications , 2012 .

[11]  Ke Yin,et al.  Highly stable, monolithic, single-mode mid-infrared supercontinuum source based on low-loss fusion spliced silica and fluoride fibers. , 2016, Optics letters.

[12]  P. Petropoulos,et al.  Mid-IR Supercontinuum Generation From Nonsilica Microstructured Optical Fibers , 2007, IEEE Journal of Selected Topics in Quantum Electronics.

[13]  Yi Yu,et al.  1.8-10  μm mid-infrared supercontinuum generated in a step-index chalcogenide fiber using low peak pump power. , 2015, Optics letters.

[14]  V. Mashinsky,et al.  Germania-based core optical fibers , 2005, Journal of Lightwave Technology.

[15]  Xuelu Zou,et al.  Spectroscopic properties and mechanisms of excited state absorption and energy transfer upconversion for Er3+-doped glasses , 1993 .

[16]  Réal Vallée,et al.  In-amplifier mid-infrared supercontinuum generation. , 2015, Optics letters.

[17]  H. Tu,et al.  How long wavelengths can one extract from silica-core fibers? , 2013, Optics letters.

[18]  B. H. Chapman,et al.  Mid-infrared Raman-soliton continuum pumped by a nanotube-mode-locked sub-picosecond Tm-doped MOPFA. , 2013, Optics express.

[19]  Shibin Jiang,et al.  High-spectral-flatness mid-infrared supercontinuum generated from a Tm-doped fiber amplifier. , 2012, Applied optics.

[20]  S Sakaguchi,et al.  Optical properties of GeO2 glass and optical fibers. , 1997, Applied optics.