We designed, manufactured and characterized two birefringent microstructured fibers that feature a 5-fold increase in polarimetric sensitivity to hydrostatic pressure compared to the earlier reported values for microstructured fibers. We demonstrate a good agreement between the finite element simulations and the experimental values for the polarimetric sensitivity to pressure and to temperature. The sensitivity to hydrostatic pressure has a negative sign and exceeds −43 rad/MPa × m at 1.55 μm for both fibers. In combination with the very low sensitivity to temperature, this makes our fibers the candidates of choice for the development of microstructured fiber based hydrostatic pressure measurement systems.

The ability to shape the index profile of optical fibers holds the key to fully flexible engineering of their optical properties and future applications. We present a new approach for the development of a graded index fused silica fiber based on core nanostructurization. A graded index core is obtained by means of distribution of two types of subwavelength glass rods. The proposed method allows to obtain arbitrary graded distribution not limited to the circular or any other symmetry, such as in the standard graded index fibers. We have developed a proof of concept fiber with parabolic refractive index core and showed a perfect match between its predicted, designed and measured properties. The fiber has a core composed of 2107 rods of 190 nm of diameter made of either pure fused silica or Ge-doped fused silica with 8.5% mol concentration. The proposed method breaks the limits of standard fabrication approaches used in fused silica fiber technology.

An all-normal dispersion supercontinuum generation in the range of 950 ÷ 1100 nm in photonic crystal fiber with core infiltrated with toluene is reported. The regular lattice hollow core photonic crystal fiber with a large core of 12 μm was designed and developed. The photonic crystal fiber core was selectively filled with toluene. The investigated fiber has normal dispersion in the wavelength range of 0.5 ÷ 2μm, while the absolute value of dispersion varies from 150 to 5 ps/nm/km in the range of 1 ÷ 2µm wavelength. The fiber nonlinear coefficient is 130 W⁻¹km⁻¹ as a result of the trade-off of high nonlinearity of toluene and a large mode area of the fundamental mode. The large mode area is required for the efficient delivery of high power pulses from large mode area input fiber in an all fiber system. As a pump source, a standard subpicosecond fiber laser emitting at 1030 nm with 10nJ pulse energy was used.

A photonic crystal fibre with hollow core filled with toluene is considered as a new system for coherent supercontinuum generation. The dispersion characteristics are studied for various geometrical parameters of photonic crystal fibres. Two structures with lattice constant 2 μ m, filling factors d /Λ 0.3 and 0.35 and toluene core of diameters of 3.34 and 3.23 μ m have flat dispersion in the near infrared range. The structure with d /Λ = 0.3 has all-normal dispersion characteristics in whole near-infrared wavelength range, while the second structure ( d /Λ = 0.35) has anomalous dispersion for wavelengths longer than 1.5 μ m. Although confinement losses in the considered structures are as high as 0.4 dB cm ⁻¹ , we show that the generation of coherent supercontinuum in the range 1.0–1.7 μ m with the pulse energy conversion of 16% is feasible in 4 cm long fibre samples with standard fibre femtosecond lasers.

We demonstrate a polarized all-normal dispersion supercontinuum generated in a birefringent silica microstructured fiber spanning beyond 2.5 µm. To our knowledge, this is the spectra reaching the furthest in mid-infrared ever generated in normal dispersion silica fibers. The generation process was studied experimentally and numerically with 70 fs pump pulses operating at different wavelengths on short propagation distances of 48 mm and 122 mm. The all-normal operation was limited by the zero-dispersion wavelength at 2.56 µm and spectral broadening was stopped by OH absorption peak at 2.72 µm. We identified the asymmetry between propagation in both polarization axes and showed that pumping along a slow fiber axis is beneficial for a higher degree of polarization. Numerical simulations of the generation process conducted by solving the generalized nonlinear Schrödinger equation (NLSE) and coupled NLSEs system showed good agreement with experimental spectra.

We report the development of microscopic size gradient index vortex masks using the modified stack-and-draw technique. The vortex mask has a form of flat surface all-glass plate. Its functionality is determined by an internal nanostructure composed of two types of soft glass nanorods. The generation of optical vortices with charges 1 and 2 is demonstrated.