A novel chalcohalide fiber with high nonlinearity and low material zero‐dispersion via extrusion

Abstract

High nonlinear fibers with low zero‐dispersion wavelength (ZDW), high laser power tolerance and large band‐gap are urgent for all‐optical‐band supercontinuum (SC) generations. Widely used chalcogenide fibers usually have a large ZDW and low laser power tolerance, and thus are not ideal for such purpose. Here, an ultra‐low material ZDW chalcohalide (ChH) glass fiber with high nonlinearity as well as high laser power tolerance has been fabricated successfully via a novel peeling‐off‐extrusion method. The step‐index fiber has double‐cladding structure, the inner cladding is GeGaSe‐CsI glass and the outer one is GeSbS jacket. The core glass has an ultra‐low material ZDW of 3.5 μm and large absorption edge of 2.0 eV. The nonlinear refractive index is 6.67 × 10−18 m2/W @1.55 μm. Broadband SC generation covering 1.05‐13.0 μm is demonstrated in this novel ChH fiber. Such glass fiber with high nonlinearity, wide transparent range, low ZDW and high laser damage threshold is promising for the applications in the mid‐infrared.

High extinction‐ratio microstructure fiber based on chalcogenide glasses

“…If the absorption peak coincides with the center of the pump wavelength, the influence of the absorption peak will be eliminated with high peak laser power and strong nonlinearity. 24 Therefore, when the pump wavelengths are 4 and 5 μm, the flat and broaden SC spectra spanning from 1.5 to 12.4 μm and 1.6 to 12.3 μm are generated at −30 dB with little influence of the absorption of Se-H absorption peak, which are shown in Figure 12A, respectively. And the spectrum is expanded to the greatest extent with the 4 μm pump wavelength at 23 mW.…”

Ga‐Sb‐S‐I chalcohalide glasses and fibers for mid‐infrared applications

“…As to the λ 0 , some researchers 33,34 think it is related to the optical bandgap E g (or λ S ). This is in good agreement with the empirical Miller's rule, 32 which implies that the glass with a higher n 0 commonly has a higher n 2 .…”

“…This is in good agreement with the empirical Miller's rule, 32 which implies that the glass with a higher n 0 commonly has a higher n 2 . As to the λ 0 , some researchers 33,34 think it is related to the optical bandgap E g (or λ S ). In order to obtain glasses with shorter λ 0 for nonlinear optical applications (eg, supercontinuum generation), they tried to raise the E g or reduce the λ S by composition modifications.…”

Mid-infrared supercontinuum generation in chalcogenide glass fibers: a brief review

“…ChH glasses combining chalcogen with halogen or metal halide offer a path for tuning optical properties, such as optical band-gap, transmission window, refractive index, etc. Taking GeSe 2 -Ga 2 Se 3 -CsI as an example [96], the optical band-gap increases gradually with the content of CsI, as shown in Fig. 18a, resulting in the increase of absorption edge and excellent transmission at shorter wavelength.…”