Supercontinuum generation in photonic crystal fibers infiltrated with tetrachloroethylene

Hieu Van Le,Van Cao Long,Hue Thi Nguyen,Ryszard Buczynski,Van Thuy Hoang,Rafał Kasztelanic

doi:10.1007/s11082-021-02820-3

Abstract

This study proposes a photonic crystal fiber made of fused silica glass, with the core infiltrated with tetrachloroethylene (C2Cl4) as a new source of supercontinuum (SC) spectrum. We studied numerically the guiding properties of the several different fiber structures in terms of characteristic dispersion, mode area, and attenuation of the fundamental mode. Based on the results, the structural geometries of three C2Cl4-core photonic crystal fibers were optimized in order to support the broadband SC generations. The first fiber structure with lattice constant 1.5 μm and filling factor 0.4 operates in all-normal dispersion. The SC with a broadened spectral bandwidth of 0.8–2 μm is generated by a pump pulse with a central wavelength of 1.56 μm, 90 fs duration and energy of 1.5 nJ. The second proposed structure, with lattice constant 4.0 μm and filling factor 0.45, performs an anomalous dispersion for wavelengths longer than 1.55 μm. With the same pump pulse as the first fiber, we obtained the coherence SC spectrum in an anomalous dispersion range with wavelength range from 1 to 2 μm. Meanwhile, the third selected fiber (lattice constant 1.5 μm, filling factor 0.55) has two zero dispersion wavelengths at 1.04 μm and 1.82 μm. The octave-spanning of the SC spectrum formed in this fiber was achieved in the wavelength range of 0.7–2.4 μm with an input pulse whose optical properties are 1.03 μm wavelength, 120 fs duration and energy of 2 nJ. Those fibers would be good candidates for all-fiber SC sources as cost-effective alternatives to glass core fibers.

Highlights

Supercontinuum (SC) lasers, i.e. light sources exhibiting an ultra-broad band of frequencies and good quality beam (Liu et al 2019), have been a subject of intense research over the past decade
A number of techniques have been proposed for the generation of SC in which the high nonlinearities and low dispersion profiles play important roles
The nonlinear coefficient of the silica-core photonic crystal fibers (PCFs) can be enhanced by reducing its effective core area, this approach will lead to difficulties in light coupling

Summary

Introduction

Supercontinuum (SC) lasers, i.e. light sources exhibiting an ultra-broad band of frequencies and good quality beam (Liu et al 2019), have been a subject of intense research over the past decade. A second common approach is to use highly nonlinear soft glass materials such as chalcogenide (Dai et al 2018), tellurite (Nguyen et al 2019; Klimczak et al 2019) or lead–bismuth–gallate glass (Buczynski et al 2010) These fibers are incompatible with silica for fusion splicing, limited in power handling, and usually require complex pump systems. CS2 has a high nonlinear refractive index n2 = 220 × 10–20 m2/W at the wavelength of 1030 nm (Kedenburg et al 2014), 100 times higher than for fused silica n2 = 2.19 × 10–20 m2/W (Kabaciński et al 2019) and are transparent in the visible to near-IR (0.5–2.2 μm) range (Churin et al 2013), it is a highly toxic, carcinogenic and explosive (Challenor 2002). The advantages of the selected PCFs would be discussed

Numerical modeling of the PCF

Modeling modal and dispersion properties of the PCF

Supercontinuum generation in optimized structures

Conclusion