Zhiyun Hou

Design and Analysis of a Microstructure Ring Fiber for Orbital Angular Momentum Transmission

In this paper, we propose a novel microstructure fiber with annular core for transmitting optical orbital angular momentum (OAM), and the OAM modes are calculated under different structure parameters of the fiber. Compared with the previous hollow step-index ring fiber, the proposed fiber brings higher refractive index contrast between the ring core and the cladding region by using only the single material of silica. The designed fiber can support more well-separated OAM modes with both thin and thick rings. Simulation results show that the novel microstructure ring fiber is promising to be applied in fiber-based OAM multiplexing in order to improve communication capacity.

A Surface Plasmon Biosensor Based on a D-Shaped Microstructured Optical Fiber With Rectangular Lattice

A numerical investigation of a surface plasmon biosensor based on D-shaped microstructured optical fiber (MOF) with rectangular lattice is presented. A full-vector finite-element method is applied to analyze the resonance coupling properties. By adjusting the diameters of two large air holes, the proposed biosensor shows excellent performance. High sensitivity and narrow full-width at half-maximum (FWHM) can be achieved. In particular, the figure of merit can reach to 478.3RIU-1, which is to our knowledge the highest among the reported MOF sensors. In the last part, the influence of coating thickness on the sensing performance has been considered.

Yb-doped silica glass and photonic crystal fiber based on laser sintering technology

We demonstrate the fabricating method for Yb3+-doped silica glass and double-cladding large mode area photonic crystal fiber (LMA PCF) based on laser sintering technology combined with a liquid phase doping method. The doped material prepared shows the amorphous property and the hydroxyl content is approximately 40 ppm. The attenuation of the fabricated LMA PCF is 14.2 dB m−1 at 976 nm, and the lowest value is 0.25 dB m−1 at 1200 nm. The laser slope efficiency is up to 70.2%.

Design and fabrication of ytterbium-doped photonic crystal fiber with low non-linearity

We report on an ytterbium-doped photonic crystal fiber fabricated by laser sintering technology combined with a solution doping method. This novel fabrication process has never been reported to the best of our knowledge. Together with low non-linearity, this PCF combines the advantages of high pump absorption efficiency and bend-insensitive, which makes this fiber predestinated for the high power fiber laser applications. The fiber laser experiment was conducted with a simple Fabry–Perot cavity to verify the performance of the PCF. A high slope efficiency of ~70.6% was obtained from a 1.5 m-long fiber. During the experiment, no roll over was observed up to the highest power level, which was only limited by the available pump power. The experimental results reveal the enormous output power scaling potential of the PCF.

U-Shaped Photonic Crystal Fiber Based Surface Plasmon Resonance Sensors

A surface plasmon resonance sensor based on a U-shaped photonic crystal fiber with a rectangular lattice has been designed through finite element method. The U-shaped fiber exhibits not only stronger mechanical strength but also better sensor performance than our previous scheme. The upper detection limit extends to higher analyze refractive index, 1.384, for phase interrogation. We introduce a ratio to evaluate the impact of higher order plasmonic mode. For wavelength modulation scheme, the parameter to describe the performance of a sensor is chosen to be the figure of merit, which can be up to 533.8[RIU−1] around complete coupling condition.

Surface Plasmon Biosensor Based on a D-shaped Microstructured Optical Fiber with Rectangular Lattice

We investigate the coupling characteristics of two structures via finite element method (FEM). It indicates that the influence on sensor sensitivity caused by birefringence at d1=0.8and the polarization by embedded ethanol is almost similar.

Analysis of supermode and structural characteristics of octagonal multicore photonic crystal fiber with large effective mode area and low confinement loss

Abstract. An octagonal multicore photonic crystal fiber is proposed. The supermode and its far field distribution have been analyzed by using the full-vector finite element method. In the condition of in-phase supermode, the influences of different wavelengths, air filling fraction, and air hole diameter between cores on normalized intensity of cores are studied. The equal intensity distribution of cores in the output plane is realized. Finally, the effects of changing the air hole diameter between different cores on the effective mode area and confinement loss are investigated. The results show that the effective way to change the relative intensity between cores is to resize the air holes between different cores. If this parameter is changed, a better intensity distribution with large effective mode area and low confinement loss for propagation is obtained.

Optical properties of the Yb/Er co-doped silica glass prepared by laser sintering technology

Yb/Er co-doped silica glass is the critical core material in the fabrication for Yb/Er co-doped optical fiber. In this paper, we demonstrate the novel laser sintering technology for making the Yb/Er co-doped silica glass rod, and analyze its physical and optical properties. The experimental results show that the fabricated silica glass is amorphous, and Yb3+/Er3+ ions uniformly distribute in the glass matrix. The material presents very good emission property around 1535 nm, and the calculation result of the gain cross section also indicates the good gain property at the emission band. Moreover, the Judd-Ofelt analysis results show that the material has very attractive spectroscopic parameters. These results can be used as good reference for the fabrication of Yb/Er co-doped optical fibers used for high-power fiber lasers in the future.

Research on ytterbium-doped photonic crystal fiber amplifier for the femtosecond fiber laser

We report on a single-stage, high-repetition photonic crystal fiber amplifier working at 1030 nm seeded by a femtosecond fiber laser, which generates an output with average power of 2.23 W at a repetition rate of 49.5 MHz and a 3 dB spectral width of 5 nm, corresponding to a pulse energy of 45.2 nJ. After amplification, the spectrum of the femtosecond laser is broadened. A home-made, ytterbium-doped, double-clad photonic crystal fiber fabricated by laser sintering technology combined with a solution doping method with a core diameter of only 24 μm is used as the power amplifier medium. The spectral characteristics as well as the suppression of amplified spontaneous emission are discussed in detail. Experiment confirms that the amplified spontaneous emission becomes negligible with increasing incident seed power and no obvious nonlinear effects arise in this experiment. These results can provide motivation for the application of ytterbium-doped photonic crystal fiber and can provide a potential application for the high-power, all-fiber laser in the future.

Design and Characterization of Bio-Chemical Sensor Based on Photonic Crystal Fiber with Fluorine-Doped Tin Oxides Film

The Mid-infrared waveband plays an important role in the biochemical sensing and material analysis, while the silica glass fiber is rarely used in the mid-infrared region due to the high transmission loss, and most of the silica glass fiber sensors are only used for testing refractive index. In order to achieve both of the concentration and functional groups of biological sample simultaneously, in this paper, we proposed a dual-channel integrated photonic crystal fiber sensor with fluorine-doped tin oxide (FTO) based on the unique optical properties of photonic crystal fibers and FTO. The surface plasmon polaritons (SPP) of FTO in the mid-infrared region has high sensitivity to the refractive index of surrounding material. Theoretical result shows that the confinement loss of the proposed fiber can be close to zero realized by a kind of unique super mode. Meanwhile, it also has a good structural error-tolerant rate, which reduces the difficulty of preparation. These findings have potential to apply the mid-IR waveband to detect multiple physical quantities simultaneously in the biochemical sensing field.