All-Normal Dispersion Chalcogenide PCF for Ultraflat Mid-Infrared Supercontinuum Generation

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. Abstract-We numerically study the dispersion-engineered chalcogenide photonic crystal fiber (PCF) which allows us to generate ultraflat broadband supercontinuum (SC) spectra in allnormal dispersion regime. A 1-cm-long chalcogenide hexagonal PCF made using Ge11.5As24Se64.5 glass pumped at 1.55 µm produced a SC bandwidth 700 nm at a peak power of 1 kW. By shifting pump at 2 µm, SC spectra can be extended with a bandwidth of 1900 nm at the same peak power level. In both cases, nonuniform spectral power distribution observes over the entire output bandwidth owing to the lower dispersion slop on the long wavelength side of the dispersion curve. To spanning SC further in the mid-infrared as well as to reduce the spectral asymmetry, we optimize another design for pumping at 3.1 µm in such a way that the pump source can be employed vicinity to the peak of the dispersion curve. Employing the largest pump peak power up to 5 kW, SC can be extended up to 6 µm (1.5 octaves) and the power distribution among the spectral components over the entire SC bandwidth can be improved significantly by this design. To enhance the spectral flatness, we optimize a second PCF geometry by reducing its pitch length and it is possible to obtain ultraflat coherent SC spanning from 2 µm to 5.5 µm (>1 octave) by this structure maintaining nearly symmetric power distribution between both side of its spectral components. Permanent repository link

Numerical Analysis of Supercontinuum Generated Microstructured Optical Fiber with all Normal Chromatic Dispersion

“…The achieved input powers are 1.6 kW at 1.06 μm center wavelength, 2.4 kW at 1.30 μm center wavelength and 3.8 kW at 1.55 μm center wavelength; with acquired fiber length LF of 6 m for all center wavelengths considered. These Pin values are higher and LF values are lower than those reported light sources in references[7][8][9][10][11][12][13].…”

“…Moreover, the proposed M-PCF exhibits an ultra-flattened chromatic dispersion of 0.0 ~ -4.5 ps/(nm.km) and broad supercontinuum spectrum in the targeted wavelength range, making it suitable for optical transmissions and SC generation applications. The proposed M-PCF also exhibits high power and short fiber length at center wavelength 1.06 μm, 1.30 μm and 1.55 μm, which are superior to that in references [7][8][9][10][11][12][13].…”

“…High nonlinear coefficient is also crucial for the generation of supercontinuum (SC) spectrum. Till now, super-luminescent diodes (SLDs) [7,8], femtosecond pulse laser sources [9][10][11][12] and picosecond pulse laser source [13] have been investigated as broadband light sources. Generation of SC spectrum with 80 nm bandwidth and 2 mW to 15 mW output power centered at approximately 1.2 μm wavelength have been demonstrated by Shibita et al [7].…”

“…Zaytsev et al [9] reported an SC spectrum pumped with 200 fs Yb-doped fiber laser at central wavelength of 1.07 μm, to obtain 11 nm spectrum FWHM and 800 mW output power. Karim et al [10] and Ahmad et al [11] demonstrated the use of 1 kW and 100 W input peak power to generate SC spectrum at 1.55 μm centre wavelength, with chalcogenide glass core. In reference [12], input peak power of 1.38 kW has been used to generate SC spectra at centre wavelength of 1.3 μm and 1.65 μm.…”

Machine learning approach for computing optical properties of a photonic crystal fiber

“…Other specific fiber properties, including effective index (n eff ), propagation constant, effective mode area (A eff ), dispersion (D), non-linearity, birefringence and confinement loss (α c ) can be easily controlled by changing the holes size, spacing between them and number of air-hole rings. The unique properties of PCF over standard optical fibers has motivated researchers to use PCF for supercontinuum generation [3,4], Raman scattering [5,6], fiber laser [7], optical sensors [8,9], spectroscopy [10], among other applications.…”