Numerical demonstration of widely tunable femtosecond soliton generation in chalcogenide microstructured fibers

Abstract

We numerically investigated widely tunable femtosecond solitons spanning from 4.1 to 7.2 µm in designed chalcogenide fibers with two rings of air holes. The core was made of Ge 15 Sb 15 Se 70 glass and the cladding glass was composed of Ge 20 As 15 S 65 . By using a 4.1 µm fiber laser with a pulse width of 100 fs as the pump light and 1 m long chalcogenide microstructured fibers as the nonlinear media, widely tunable femtosecond solitons spanning from 4.1 to 7.2 µm were observed, and the pulse width of these tunable Raman solitons remained below 150 fs. The efficiencies of the mid-infrared soliton could be up to over 80%, ranging from 4.1-6.8 µm. Through numerical simulations, we also observed red-shifted dispersive waves varying from 10.2 to 8.9 µm. Our simulated results show that the designed chalcogenide microstructured fibers are promising nonlinear media for generating tunable mid-infrared light sources.

Numerical Demonstration of the Soliton Self-Frequency Shift Process Beyond 8 μm in a Tellurite-Chalcogenide Fiber Cascaded Structure

“…where f R is the Raman contribution to the total nonlinear response and is 0.29 [17] for the TBY fiber. h R (t) is the delayed Raman response:…”

“…Despite the fluoride and tellurite fibers have successfully extended the SSFS process to a longer wavelength range, their performance would greatly worsen in the spectrum beyond 4.5 μm for the steeply increasing fiber loss. Another promising candidate is the chalcogenide fiber, which offers low fiber loss even in the spectrum beyond 5 μm [17]. It has the potential to achieve further wavelength extension.…”

“…Though great achievements have been made in experiments, the proceedings in the field of theory have been slow in recent years. Most theoretical works were aimed at offering theoretical accordance with the experiments [6], [12], [15] or predicting the SSFS performance in some designed or newly manufactured Raman shifter fibers [14], [17]. However, there are many questions in experiments waiting to be answered in the theory.…”

“…Nevertheless, these issues have not been clarified by theoretical works. Although chalcogenide fiber is the most promising candidate for wavelength extension beyond 5 μm through the SSFS effect, current theoretical works [17], [40] only demonstrated it with unrealized seed pulse. There have been no theoretical works pointing a feasible path to utilize its enormous potential up to now.…”

Numerical demonstration of mid-infrared temperature sensing by soliton self-frequency shift in a fluorotellurite microstructured fiber

“…To ensure the accuracy of numerical simulations, a fourth-order Runge-Kutta algorithm was adopted. 2 18 time (4) and frequency discretization points and a longitudinal step length < 4 μm were used during the calculation [42].…”