Zhijia Hu

High birefringence photonic crystal fiber with high nonlinearity and low confinement loss

A particular photonic crystal fiber (PCF) designed with all circle air holes is proposed. Its characteristics are studied by full-vector finite element method (FEM) with anisotropic perfectly matched layer (PML). The simulation results indicated that the proposed PCF can realize high birefringence (up to 10(-2)), high nonlinearity (50W(-1)·km(-1) and 68W(-1)·km(-1) in X and Y polarizations respectively) and low confinement loss (less than 10(-3)dB/km at 1.55um wavelength).

Disordered microstructure polymer optical fiber for stabilized coherent random fiber laser

We have demonstrated the realization of a random polymer fiber laser (RPFL) based on laser dye Pyrromethene 597-doped one-dimensional disordered polymer optical fiber (POF). The stabilized coherent laser action for the disordered POF has been obtained by the weak optical multiple scattering of the polyhedral oligomeric silsesquioxanes nanoparticles in the core of the POF in situ formed during polymerization, which was enhanced by the waveguide confinement effect. Meanwhile, the threshold of our RPFL system is almost one order of magnitude lower than that of the liquid core random fiber laser reported previously, which promotes the development of random lasers.

A theoretical model of a cylindrical luminescent solar concentrator with a dye-doping coating

A novel configuration for a luminescent solar concentrator is proposed, which employs a cylindrical waveguide with a dye-doping coating and is here called a cylindrical coated luminescent solar concentrator (CC LSC). An expression for the power conversion efficiency of the configuration is first established, and then its loss mechanisms, such as escape-cone loss, self-absorption probability, and host absorption, are investigated in terms of the theoretical model. Results are also compared with those for a cylindrical doped luminescent solar concentrator (CD LSC), from which it can be concluded that the power conversion efficiency for a CC LSC is 1.17–1.48 times as much as that for a CD LSC with an equivalent absorbance and geometric gain when Rhodamine 6G is used as a luminescent species and the ratio of the coating thickness to the radius of the cylinder, d/R, is 1/100. It is also found that the power conversion efficiency for a CC LSC increases with decreasing d/R at a certain geometric gain.

Polarized random laser emission from an oriented disorder polymer optical fiber

We demonstrate the realization of a polarized random polymer fiber laser (RPFL) in the different disordered gain media doped polymer optical fibers (POFs). Multiple scattering of disordered media in the orientated POF was experimentally verified to account for polarized lasing observed in our RPFL system. This Letter presents a new avenue for fabricating polarized RPFLs in a large scale. Meanwhile, the polarization-maintaining property of random lasing for different disorder POF are researched, which will open a window to designing a polarization-maintaining random fiber laser.

Dual-Core Photonic Crystal Fiber for Use in Fiber Filters

An asymmetrical dual-core photonic crystal fiber (DC-PCF), which possesses all circular air holes, is proposed. By setting appropriate geometrical parameters, the wavelength-selective coupling property is realized, and a compact optical filter with a short length of 1.83 mm based on the DC-PCF is designed. The spectral transmission characteristics of the filter are investigated by the beam propagation method. The results demonstrate that the optical filter possesses a bandwidth of ~58 nm and small sidelobes. The proposed optical filter could be used in the integrated optical systems.

Gold nanoparticle-based plasmonic random fiber laser

We have reported the realization of a plasmonic random fiber laser based on the localized surface plasmonic resonance of gold nanoparticles (NPs) in the liquid core optical fiber. The liquid core material contains a dispersive solution of gold NPs and laser dye pyrromethene 597 in toluene. It was experimentally proved that the fluorescence quenching of the dye is restrained in the optical fiber, which is considered one of the main sources of loss in the traditional laser system. Meanwhile, the random lasing can be more easily obtained in the random laser system with more overlap between the plasmonic resonance of the gold NPs and the photoluminescence spectrum of the dye molecules.

Modulation of large absolute photonic bandgaps in two-dimensional plasma photonic crystal containing anisotropic material

The large absolute photonic bandgaps of two-dimensional (2D) anisotropic magnetic plasma photonic crystals with hexagonal and square lattices are obtained by introducing tellurium dielectric rods using the modified plane wave expansion method. Equations for calculating the band structures in the irreducible part of the first Brillouin zone are theoretically deduced. The modulation properties indicate that the location and bandwidth of the absolute photonic bandgaps (PBGs) could be tuned by filling factor, plasma frequency, and magnetic field. The effective tunable ranges and critical values of these parameters are found. These results could be helpful in designing 2D anisotropic PPCs with large absolute PBGs.

Random lasing from dye doped polymer optical fiber containing gold nanoparticles

We have demonstrated the realization of a plasmonic random polymer fiber laser (RPFL) based on gold nanoparticles (NPs) doped one-dimensional disordered gain polymer optical fiber (POF). In this work, the plasmonic RPFL is fabricated by directly drawing from a laser dye and gold NPs system codoped POF. The random lasing can be obtained from the waveguide-plasmon-scattering in the POF system. Meanwhile, the dye doped fiber in the presence gold NPs has high photostability.

Wavelength control of random polymer fiber laser based on adaptive disorder

We demonstrate the realization of two different kinds of random polymer optical fiber lasers to control the random lasing wavelength by changing the disorder of polymer optical fibers (POFs). One is a long-range disorder POF based on copolymer refractive-index inhomogeneity, and the other is a short-range disorder POF based on polyhedral oligomeric silsesquioxanes scattering. By end pumped both disorder POFs, the coherent random lasing for both is observed. Meanwhile, the random lasing wavelength of the short-range disorder POF because of a small scattering mean-free path has been found to be blue shifted with respect to the long-range disorder POF, which will give a way to control the random lasing wavelength.

Optical amplification of Eu(TTA) 3 Phensolution-filled hollow optical fiber

A liquid core optical fiber (LCOF) composed of hollow fiber and a solution of Eu(TTA)(3)Phen (TTA=2-thenoyltrifluoroacetone, Phen=1, 10-phenanthroline) in dimethyl sulfoxide (DMSO) has been fabricated, in which the concentration of Eu(TTA)(3)Phen in DMSO is 0.8 wt.%, the core diameter of the LCOF is 10 μm, and the fiber length is 8.1 cm. By the end pumping with a diode-pumped solid-state laser at 355 nm, a small optical signal at 613 nm was amplified with a gain of 8.2 dB at a pump power of 203 mW. Based on this experimental result, a liquid core optical fiber amplifier can be realized by the LCOF, which has wide potential applications in many optical devices.