Optical properties of all-solid microstructured optical fibers

Abstract

Abstract-In this Letter, we study optical properties of all-solid microstructured optical fiber made of soft glass. Such fibers have various interesting features including good geometrical stability, low fundamental transmission losses, high Kerr nonlinearity, and large solubility of rare-earth ions. By investigating the transmission mechanism, mode structure, and numerical aperture of the fibers and confronting the results with theoretical calculations we demonstrate that the fibers have optical properties similar to those observed in air-silica microstructured optical fibers. This makes the all-solid soft-glass microstructured fibers very attractive for many potential applications. [10]. While sophisticated structures of MOFs are responsible for unique properties of the fibers, they also make them very sensitive to any fluctuations of waveguide geometry. In fact, one of the major challenges of MOFs is the preservation of optical properties of the fibers along their length. This becomes particularly challenging for air-glass MOFs, as the capillaries of the fiber preform tend to collapse during fiber drawing [11]. In order to prevent such a collapse, pressure is applied during fiber fabrication. Although this technique limits sizable capillary contraction, it does not fully eliminate fluctuations in the fiber geometry, in particular, distortions of air-glass interface, which often introduce light-power losses and alter dispersion of the waveguide [11].The problem of the instability of optical properties of MOFs may be relaxed by fabrication of all-solid (AS) MOFs [11]. In that case, the geometry deviations are reduced by the application of two or more types of glass with properly matched thermal and chemical properties. A significant difference between refractive indices of glass may provide a sufficient contrast between the core and cladding allowing for the total-internal-reflection (index) guidance or the photonic-bandgap light guidance.In this Letter, we investigate optical properties of the AS MOF made of two types of soft glass (F2 and NC-21) with the respective refractive indices n F2 =1.619 and n NC =1.533, similar to those investigated in [12]. The fiber possesses hexagonal structure with the lattice constant Λ ≈ 2.5µm and d/Λ ≈ 0.65, where d is the diameter of the F2-glass rods (Fig. 1). Its core was formed by replacing seven central F2 rods with a single NC-21 rod and was surrounded by eight rings of the F2 rods constituting a microstructured cladding of the fiber [ Fig. 1(a)]. The fiber has an attenuation of ~13.1dB/m at 855nm [12]. All measurements presented in this paper were performed with a fiber of 18cm in length. (c) Scheme of the experimental setup. Depending on the investigated property, we used a diode laser operating at 795nm (the transverse mode profile and the numerical aperture measurements) or a supercontinuum source (the photonic-bandgap determination). The light was delivered to the investigated MOF trough a polarization-maintaining PANDA fiber. Detector denotes one of three types of...

Low loss poly(methyl methacrylate) useful in polymer optical fibres technology

“…The thermal studies were made by thermogravimeter connected on-line with FT-IR and QMS spectrometer, the optical properties were characterized by spectral attenuation measurements. It was found that polymer obtained in our laboratory is characterized by higher temperature (about 100 0 C) of beginning mass loss occurred and lower attenuation then commercial available polymer.Microstructured optical fibers (MOFs) provide extra degrees of freedom in manipulating the optical properties of light, such as dispersion, nonlinearity, and birefringence [1][2][3][4][5]. Therefore they have attracted increased interest over the last two decades.…”

“…Microstructured optical fibers (MOFs) provide extra degrees of freedom in manipulating the optical properties of light, such as dispersion, nonlinearity, and birefringence [1][2][3][4][5]. Therefore they have attracted increased interest over the last two decades.…”