Peng Jiang-De

Dispersion of square solid-core photonic bandgap fibers

A novel solid-core photonic bandgap (PBG) fiber with a square lattice is proposed. It is proved that light can propagate with the PBG effect in a defect core that is created by downdoping the central silica of the lattice. Compared with those of solid-core honeycomb PBG fibers, both the PBG widths and the bandwidthsof defect modes are increased in square PBG fibers. Simulations show that dispersion of this square solid-core PBG fiber is dominated by material dispersion and influenced by the PBG edges at the bandwidth boundaries.

Slow Light by Two-Dimensional Photonic Crystal Waveguides

A simple and effective way to measure the group velocity of photonic crystal waveguides (PCWGs) is developed by using a fiber Mach–Zehnder interferometer. A PCWG with perfect air-bridge structure is fabricated and slow light with group velocity slower than c/80 is demonstrated.

Fluid Sensor Based on Transmission Dip Caused by Mini Stop-Band in Photonic Crystal Slab

We propose a fluid sensor based on transmission dip caused by mini stop-band in photonic crystal slabs. Simulation results show that this novel type of sensors has large detective range (more than 1.5) and relative high-sensitivity (4.3 × 10−5 in certain conditions). The central frequency and bandwidth of the mini stop-bands depend on the structure parameters of PC waveguides, which makes it possible to optimize the detective range and detective sensitivity.

Abnormal Cutoff Thickness of Long-Range Surface Plasmon Polariton Modes Guided by Thin Metal Films

Long-range surface plasmon polariton (LRSPP) modes guided by a thin metal film surrounded by semi-infinite dielectrics with different refractive indices are studied. Our calculation results show that the cutoff thickness of the metal film does not monotonically increase with refractive index difference Δn between the substrate and superstrate. Just because of this abnormal behaviour of cutoff thickness, the existence of LRSPP illustrates complicated situations in asymmetric configurations. For a certain metal film thickness, LRSPP may exist in one, two or three refractive index difference Δn regions.

High-Quality Fiber-Based Heralded Single-Photon Source at 1.5 μm

A high-quality heralded single-photon source (HSPS) at 1.5 μm is experimentally demonstrated based on spontaneous four wave-mixing in a piece of dispersion-shifted fiber cooled by liquid nitrogen. To improve the up-limit of the preparation efficiency of the HSPS, commercial dense wavelength-division multiplexing components are used to reduce the loss of the filtering and splitting system between the fiber and the single-photon detectors. As a result, a preparation efficiency of 80% is realized under a g(2) (0) of 0.06 in our HSPS experimental system, which is the best performance for the fiber-based HSPS at 1.5 μm reported so far.

Long-Range Surface Plasmon Polaritons Guided by a Thin Metal Stripe

A long-range surface plasmon polariton (LRSPP) waveguide consisting of a 15 nm thick gold stripe embedded in a homogeneous polymer BCB is reported. LRSPPs are excited by TM-mode input light successfully using an end-fire method. By scanning the output coupling fibre, the near field of the LRSPP is measured. The propagation loss of as low as 2.34 dB/mm is demonstrated.

A novel design for all-solid silica Bragg fiber with zero-dispersion wavelength at 1550 nm

A novel all-solid Bragg fiber composed entirely of silica material is proposed in this paper. The core of this Bragg fiber is composed of conventional silica, and the cladding is formed by a set of alternating layers of up-doped and down-doped silica. This all-solid silica Bragg fiber is technically feasible and can simplify the fabrication technique. Dispersion properties of this silica Bragg fiber are investigated, and simulations show that zero dispersion wavelength lambda0 near 1.55 m with nonlinear coefficient gamma about 50 W-1km-1 can be obtained in silica Bragg fiber.

Experimental Study on Preparation Efficiency of Microstructured-Fibre Based Heralded Single-Photon Source at 1.5 μm

We present an experimental study on the microstructured-fibre (MSF) based heralded single photon source (HSPS) at 1.5 μm. The preparation efficiency is measured to be 8.7% under room temperature. The analysis of the experimental results shows that the preparation efficiency can be improved up to 22.9% by the Raman noise suppression with fibre cooling under the experimental setup parameters. Further efficiency improvement could be achieved by improving the collection efficiency and reducing dark counts of single photon detectors (SPDs). The experimental results and analysis show great potential applications of the MSF in high efficient HSPSs.

Polarization dependent dispersion and its impact on optical parametric process in high nonlinear microstructure fibre

High nonlinear microstructure fibre (HNMF) is preferred in nonlinear fibre optics, especially in the applications of optical parametric effects, due to its high optical nonlinear coefficient. However, polarization dependent dispersion will impact the nonlinear optical parametric process in HNMFs. In this paper, modulation instability (MI) method is used to measure the polarization dependent dispersion of a piece of commercial HNMF, including the group velocity dispersion, the dispersion slope, the fourth-order dispersion and group birefringence. It also experimentally demonstrates the impact of the polarization dependent dispersion on the continuous wave supercontinuum (SC) generation. On one axis MI sidebands with symmetric frequency detunings are generated, while on the other axis with larger MI frequency detuning, SC is generated by soliton self-frequency shift.

Microstructure-Fibre-Based Optical Parametric Amplification in Telecom Band with Ultra-High Gain Slope

We report a microstructure-fibre-based parametric amplification experiment in telecom band with ultra-high gain slope. A peak on-off gain of 52.3 dB is achieved using 25 m high nonlinear microstructure fibre (MF) and only 5.3 W pump power. The parametric gain slope is up to 580 dBW−1km−1. From the experimental data, the linear coefficient of the MF is estimated to be about 66.7 W−1km−1. The experiment shows the great potential of MFs in practical fibre parametric amplifiers.