Recently, use of liquid-filled PCFs has been received more attention because it overcomes the disadvantages of liquids capillary approach. However, this approach lacks flexibility in designing the dispersion and modal properties of the fibers (Churin et al. Up to date, most of the experimental results of liquid-core fibers SC generations are focused on the use of step-index liquid-core optical fibers since they are straight forward and convenient to fill micro-capillaries with liquids, as an equivalent of a step-index optical fiber. 2018), biomedical technologies (Guo et al. 2012), especially, with use of mid-IR SC laser sources in medical diagnostics (Chemnit et al. Therefore, the infiltration of PCFs with liquids adds an extra degree of freedom for broadening applications in potential fields (Ebnali-Heidari et al. Another advantage of using liquid core PCFs is that the generated SC spectra can be controlled by the modification of temperature or pressure since it is possible to alter the PCFs’ dispersion properties via these factors (Van et al. linear refractive index for practical applications (Wohlfarth 2008).

In addition, liquids are able to be mixed to optimize their optical properties, e.g. carbon disulfide (CS 2), carbon tetrachloride (CCl 4) are highly transparent in the near-IR range (Churin et al. Unlike silica, nonlinear liquids show high nonlinearity that is comparable with the nonlinear soft glasses (Kedenburg et al. 2018a Maji and Chaudhuri 2014 Pniewski et al. Secondly, more complex fiber structures may be difficult to fabricate, and may require more thermal processes which can result in crystallization.Īn alternative solution is liquid-infiltrated optical fibers, as demonstrated in previous research (Zhang et al. Other disadvantages of these glasses include the following. However, these fibers are incompatible with silica for fusion splicing, limited in power handling, and usually require complex pump systems. 2019) or lead–bismuth–gallate glass (Buczynski et al. A second common approach is to use highly nonlinear soft glass materials such as chalcogenide (Dai et al. Although the nonlinear coefficient of the silica-core PCFs can be enhanced by reducing its effective core area, this approach will lead to difficulties in light coupling. Moreover, silica shows relatively low nonlinearity, so silica fibers require input pulses with high peak power for broad SC spectra. Silica fibers work efficiently for SC generations from the visible to the near-infrared (IR) range, but not for the mid-IR range due to their limited transmission bandwidth (Dudley et al. A typical approach for this purpose is utilizing photonic crystal fibers (PCFs) made of silica or highly nonlinear soft glasses (Dudley et al. 2008).Ī number of techniques have been proposed for the generation of SC in which the high nonlinearities and low dispersion profiles play important roles. Their applications cover many areas such as spectroscopy, frequency metrology, biomedicine, and optical coherence tomography (Holzwarth et al. 2019), have been a subject of intense research over the past decade. light sources exhibiting an ultra-broad band of frequencies and good quality beam (Liu et al. Those fibers would be good candidates for all-fiber SC sources as cost-effective alternatives to glass core fibers. 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. 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. 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.

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. 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 first fiber structure with lattice constant 1.5 μm and filling factor 0.4 operates in all-normal dispersion. Based on the results, the structural geometries of three C 2Cl 4-core photonic crystal fibers were optimized in order to support the broadband SC generations. 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. This study proposes a photonic crystal fiber made of fused silica glass, with the core infiltrated with tetrachloroethylene (C 2Cl 4) as a new source of supercontinuum (SC) spectrum.

Silica zero dispersio wavelength