Thulium pumped high power supercontinuum in loss-determined optimum lengths of tellurite photonic crystal fiber

Abstract

We demonstrate the formation of an ultrabroad supercontinuum (SC) generated in short lengths of highly nonlinear tellurite photonic crystal fibers (PCFs) specifically designed for high power picosecond pumping at the thulium wavelength 1930 nm. The fibers exhibit high losses caused by material absorption below ∼500 nm and at long wavelengths >4000 nm by both material and confinement loss. The fibers are endlessly single-mode with a relative hole size of 0.4 and we tune the pitch (Λ) from 3 to 7 μm to achieve zero-dispersion wavelengths both below and above the pump. We show how the SC has a maximum width at an optimum fiber length after which the bandwidth and power decay due to losses. We thus obtain a maximum bandwidth of 4.6 μm for the PCF with the smallest Λ, i.e., 3 μm at an optimum length of only ∼2.8 cm.

Ultrabroad supercontinuum generation in tellurite equiangular spiral photonic crystal fiber

“…After this, Raman shift can be seen in the spectrum due to al. 8 reported SC using average power of 15 W, while we report here is using average power of 12 mW. Thus for an average pump power value that is lower by almost three orders of magnitude, the SC bandwidth obtained in the ES-PCF is substantial and is quite flat.…”

“…Also, the small transmission window of silica glasses (0.2-3 µm) limits the SC generation beyond this range. This limitation has attracted attention towards non -silica glasses such as lead -silicate 3 , fluoride 4 , chalcogenide 5 , and tellurite [6][7][8] glasses that have larger n 2 and some of which are transparent in the mid -infrared window.…”

Midinfrared optical rogue waves in soft glass photonic crystal fiber

“…Hence we consider a 60 cm tellurite fiber with pitch (Λ=3 μm), relative hole size (d/Λ=0.4) and zero-dispersion wavelength (ZDW) ∼1780 nm [17] see Fig. 1(a), in which we show the measured loss and calculated dispersion.…”

Nonlinear soliton matching between optical fibers

“…As an initial condition we use a fundamental soliton with a central wavelength λ p ¼ 1550 nm, and FWHM pulse duration of T FWHM ¼ 50 fs, corresponding to an Erbium laser source. In simulations we use the latest reported Raman response functions for each material [9,10]. After propagation in 10 m of fiber 1, simulation of the GNLSE shows that the soliton has redshifted to λ c ¼ 1816 nm due to the Raman effect [11], while continuously adjusting its pulse width and peak power to preserve N 1 ¼ 1 (see Table 2).…”

“…By design of the waveguide dispersion and choice of nonlinear fiber material, it is possible to Table 1. For material parameters see [4,9], [6,10], [5]. compensate for the linear power reduction from MFD mismatch.…”