Ping Shum

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We proposed a novel polarization maintaining air-core bandgap polymer fiber for terahertz (THz) wave guiding. The periodic arrangement of square holes with round corners in cladding offers bandgap effect for mode guiding. The guiding properties including transmission bandwidth, numerical aperture, phase-index birefringence, modal absorption loss and bend(More)
The concept of (∈, ∈ ∨ q)-fuzzy h-ideals of hemirings is introduced and some characterizations are described. We show that a hemiring S is h-hemiregular if and only if for any (∈, ∈ ∨ q)-fuzzy right h-ideal F and (∈, ∈ ∨ q)-fuzzy left h-ideal G, F • 0.5 G = F ∩ 0.5 G. Finally, the concept of implication-based fuzzy h-ideals of hemirings is considered.
We experimentally demonstrate switchable temporal soliton generation from a thulium-doped fiber laser (TDFL), using carbon nanotubes as the mode-locker. With the help of residual polarization dependent loss of a wavelength division multiplexer, a weak nonlinear polarization rotation (NPR) effect can be achieved within the laser cavity, which may provide(More)
In this paper, we, for the first time, systematically study a new structure of a dual-core photonic crystal fiber filled with a metal wire in the center air hole. Theoretical analysis based on the supermode theory and the coupled-mode theory shows that the directional power transfer between the two fiber cores is enhanced by the resonant coupling between(More)
In this paper, we present a detailed study on the dispersion effects in active mode-locked fiber lasers. By including fiber dispersion effect in a laser model, we find that the dispersion causes the pulse broadened and chirped. Moreover, not only the pulse position but also the lasing spectrum is shifted when the modulation frequency is detuned in(More)
A compact and low-cost approach to photonic ultra-wideband (UWB) monocycle pulse generation is proposed and experimentally demonstrated based on the wavelength dependence of the half-wave voltage of a Mach-Zehnder modulator (MZM). By employing a single MZM and two laser sources at around 1310nm and 1550nm, a pair of polarity-reversed monocycle pulses with(More)