Double-clad photonic crystal fibre structure for laser applications is demonstrated. The double-clad structure of the fibre has the air-cladding with glass bridges of waists less than 500nm. The fibre was produced with phosphate glass and the core region was doped with ytterbium. The fibre was investigated and we found it to be monomode for generation wavelength of 1008nm. Whole fibre producing process including doped and undoped glass manufacturing and fibre drawing was held in Institute of Electronic Materials Technology.
We present experimental realization of nonlinear and highly birefringent microstructure fiber fabricated from silicate glass. Using full vector FEM mode solver the numerical analysis of reported fiber is performed and its modal, polarization and dispersive properties are investigated. Particularly, the calculations reveals guidance of two orthogonally polarized eigenmodes with the difference of its effective indexes B=0.0025 for wavelength λ=1.55 μm. Additionally, spectral broadening of the 50 fs Ti:Sapphire laser impulses with average power 150mW coupled into 39 cm section of the fiber is observed.
We report on the fabrication of photonic band gap fiber made of multicomponent glass. This fiber has a hexagonal lattice made of an array of 17 x 17 air capillaries with a lattice constant Λ=6.0 μm and air holes of diameter equal to d=5.7 μm. A hollow core is created by omitting seven central microcapillaries and have diameter of 16 μm. Characterization results show that the fiber can guide the light in the visible range with a central wavelength of 510 nm. The transmission properties for the presented PCFs are measured by using a broadband light source and an optical spectrum analyzer. In the paper we discuss also possible future modifications of the structures and their potential applications.
In the paper we report on development of all-solid holey fibers. Numerical analysis of dispersion properties of such fibers is also presented. The periodic microrods that forms cladding are made of glass instead of air. Use of two or more multicomponent glasses in the fiber structure allow to manipulate refractive index contrast in the structures which is not possible in holey fibers. The all-solid holey fibers offer additional degree of freedom to the designer for determination of dispersion in fibers than in case of air-holes PCFs. Moreover a fabrication of all-solid PCFs allows to better control of geometry and uniformity of the cladding structure design.
Most works on photonic crystal fibers with a photonic bandgap are concerned with structures made of silica glass with a hexagonal lattice. However, there are many other possible choices for the crystal structure of the fiber. In this paper, we study the optical properties of photonic bandgaps in a hollow-core photonic crystal fiber with a square lattice fabricated from multi-component glass. A composition of oxides was chosen to obtain a refractive index contrast higher than in fused silica fibers. The core size of the fiber is 11 microns and the cladding is made of an array of 17 x 17 air capillaries. A full-vector mode solver using the biorthonormal basis method is employed to analyze the modal properties of the fiber. We verify the guiding properties of the fiber by FDTD simulations. The transmission properties for several lengths of the fiber were measured by using broadband light from a nanosecond-pulse supercontinuum source and an optical spectrum analyzer. Preliminary results show that light is guided around 1650 nm. Possible modifications of the structure and potential applications will be discussed.
We present experimental realization of elliptical-hole rectangular lattice photonic crystal fibres fabricated from multi-component glass. The photonic cladding has a lattice constant 2.17 μ and 3.72 μ for main axis, respectively and elliptical holes with ellipticity 2.14. The rectangular lattice is chosen to obtain two-fold geometry and to increase the global asymmetry of photonic structure, which enhance birefringence of fibre. Rectangular lattice allows also a better control of elliptical air holes uniformity during fabricating process. Fabricated fibres have a cladding with a rectangular cross-section. It allows for easy identification of the fibre's principal axes and orientation of the fibre with respect to directional measured perturbation like axial stress, bending force in sensor applications. Using a full vector plane-wave expansion method an influence of structure parameters such as ellipticity of air holes and aspect ratio of rectangular lattice on birefringence and modal properties of the fibres are studied. Potential applications of the fibres are discussed.
A range of integrated fiber optic structures - lightguides, image guides, multicapillary arrays, microstructured (photonic) fibers - manufactured in the Institute of Electronic Materials Technology (ITME) is described. All these structures are made of multicomponent glasses (a part of them melted in ITME). They can be manufactured in similar multistep process that involves drawing glass or lightguide rods and tubes preparing glass performs, stacking a bundle with rods and (or) tubes, drawing multifiber or multicapillary performs. Structure formation, technological process, characterization and applications of different integrated structures are presented.
The properties of photonic crystal fibers are determined by the structure of photonic cladding: filling factor, type of lattice and shape of air holes. The dispersion and modal characteristics of the fiber can be modified by adding an additional lattice of glass micro-rods with a refractive index higher than the glass substrate. We have fabricated a solid-core photonic crystal fiber with a double photonic cladding composed of air holes and glass micro-rods, where a high index multicomponent glass is used for the micro-rods. As a reference a fiber with similar parameters and a single lattice of air holes is fabricated. The fiber cladding is composed of 17 x 17 air holes and micro-rods ordered in square lattice. In this paper, we study the optical properties of photonic crystal fiber with single and double lattices. FDTD method and a full-vector mode solver based on biorthonormal basis method are used for fiber analysis. Possible modifications of the structure and potential applications will be discussed.
In photonic crystal fiber technique a free choice of microstructure allows flexible design of multicore waveguides. In this paper we study properties of a double-core fiber with square and hexagonal lattices. They can be modified with local changes of a structure. Variable size of the central hole that separates cores influences mode coupling properties. Full-vector mode solver using the biorthonormal basis method is employed to analyze guiding properties of the double-core fiber. In FDTD numerical simulations we study coupling efficiency in fibers with various crystal structures. We present experimental realizations of solid double-core photonic crystal fibers fabricated from multi-component glass. Composition of oxides is chosen to obtain higher refractive index than available in fused silica and relatively low-loss guidance when compared to other silicate glasses. Transmission properties of double-core fibers are measured, inter-core coupling mechanism and possible applications are discussed.
We present the results of modeling of photonic crystal fibers with a square lattice and square holes. In photonic fibers having an order m = 2 symmetry the degeneracy of the fundamental mode that is a combination of the polarization modes HE11x and HE11y disappears. The advantage of the square structure is that the photonic crystal fiber becomes very sensitive to deformations caused by external factors yet it remains highly birefringent. The propagation constants of both modes were calculated using the vector method of biorthonormal bases. The use of a square lattice in a photonic crystal fiber makes possible to achieve birefringence of the order of 10-2. We have examined the dependence of birefringence on the geometrical parameters of the fiber's structure.
Most works on photonic crystal fibers used for telecommunication are concerned with the structure of single mode fibers with a hexagonal lattice. However, there are many other possible choices of the fiber's crystal structure. In this paper we present a comparison of the basic characteristics of the photonic crystal fibers with hexagonal and rectangular crystal lattices and of the resulting differences in the structure's axial symmetries. Like in natural crystals the number of the axes of symmetry implies different optical characteristics of the photonic structures. In order to compare the properties of the photonic fibers with a hexagonal and rectangular lattices we use a vector method of biorthonormal bases. We also present a possible technology of manufacturing fibers with different crystal structures.
The freedom in choosing a crystal structure of the photonic fiber makes possible to manufacture fibers with more than one core. In this paper we present simulations of the characteristics of a double-core photonic crystal fiber with a square lattice. Such fiber can be used in telecomunication switches. The simulations of the modal structure were done using a vector method of biorthonormal bases. The results show that a double-core crystal, which exhibits mode coupling between cores fiber, can be designed. We present preliminary results of manufacturing of a double-core photonic fiber and measurements of its transmission characteristics.