Papers by Keyword: Photonic Crystal Fiber (PCF)

Abstract: A dual-core photonic crystal fiber (PCF) with high birefringence, short coupling length and broadband flat dispersion is proposed in the paper. The symmetry of the original symmetric structure composed of hexagonally distributed air holes is distorted by replacing the innermost 12 air holes with 6 elliptical air holes. The characteristics of the dual-core PCF such as birefringence, coupling length and chromatic dispersion are analyzed by tuning its structural parameters. The results demonstrated that the dual-core PCF exhibits simultaneously a birefringence of up to 10^-2, a coupling length of 68.178 for the x-polarization and 74.825 for the y-polarization, and a broadband flat dispersion ranging from 1.1 to 1.6. The novel dual-core PCF may find applications in polarization-maintaining fibers and fiber-based polarization beam splitters/couplers with broadband flat dispersion.

Abstract: A coupler of single mode fiber with photonic crystal fiber with a coupling ratio of 0 to 90% was fabricated with a new method called Auto-deposition Fused Side-adhere. A model for coupler of side-polished single mode fiber with side-polished photonic crystal fiber was established which proves it feasible to make such a coupler practically. In the range of 1520~1620nm, the Wavelength Dependent Loss (WDL) of the through port was 0.3dB and of the coupled port was 5dB. The Polarization Dependent Loss of through port was 0.25dB and 0.31dB at 1310nm and 1550nm, and the WDL of coupled port was 1.46dB and 1.75dB. When temperature changed from 10°C to 80°C and humidity changed from 10% to 70%, coupling ratio changed about 7% to 16%. It can be concluded that a steady coupler of single mode fiber with photonic crystal fiber can be made with the Auto-deposition Fused Side-adhere Coupling method, which can give a reference method and lay an experimental foundation for the fabrication of photonic crystal fiber coupler.

Abstract: A silver film-covered photonic crystal fiber containing different sizes of air holes is proposed to construct the surface plasmon resonance sensor. In this sensor, a nanoscale metal film and analyte can be deposited on the outer side of the fiber instead of coating or filling in the holes of the conventional PCF, which make the real time detection with high sensitivity easily to realize. Moreover, it is relatively stable to the changes of the diameter of air holes, which is very beneficial for sensor fabrication and sensing applications. The finite element method is used to analyze the characteristics of the surface plasmon resonance sensor. And the numerical results show that the resonance wavelength is sensitive to the refractive index of liquid, while the resonance wavelength doesn’t change basically when the diameter of air holes vary.

Abstract: In this paper we present the basic theory of nonlinear photonic crystal fibers (PCFs) with a focus on theoretical aspects of generating squeezed light using Kerr effect. The FDTD method is employed to study the guided modes of em field propagation in PCF. The degree of squeezing is determined using correlations function corresponding to the fields of light. It is shown that noise in a squeezed light is reduced to about 24% below the minimum noise observed in coherent light.

Abstract: The photonic crystal fiber was applied in high-power laser gain medium, because of its flexible and optical controllability and special structure, which can overcome the design flaws of common optical fibers effectively. This paper studied the Yb3+ doping double-clad photonic crystal fiber. Through the theoretical analysis and numerical simulation, it optimized the structure design, drew the high doping concentration and double-clad fiber samples, analyzed the absorption and fluorescence spectra of fiber core material, and tested the optical fiber spectrum features, which can improve the performance of high power fiber laser.

Abstract: A novel kind of high birefringent terahertz (THz) photonic crystal fibers (PCFs) with material-filled structure is proposed in this paper. Based on the material-filled technology, which different materials are selectively filled into four air holes of the inner first circle near the central core in the designed THz PCFs, high birefringence are obtained from the structural and material-filled induced asymmetry in large frequency ranges near 1THz. Modal birefringence with different structural parameters and diverse refractive indices of the filled materials are investigated by plane wave expansion (PWE) method. The numerical results show that high birefringence up to 10^-3 can be obtained and its structure is simpler than that of the early proposed highly birefringent THz PCFs. It is helpful for PCFs design and real fabrication in the potential THz applications.

Abstract: A novel high-birefringent photonic crystal fiber (PCF) was proposed and analyzed by full-vector finite element method (FEM). The modal field and birefringence properties were investigated. All of air holes in proposed PCF are round, and their diameters are the same. It is greatly reduce the difficulty of fabrication. According to the results of numerical analysis, it can be observed that the mode birefringence of this novel PCF can be easily achieve the order of 10^-3 at 1.55μm. This research provides effective theoretical method for the fabrication, development and construction of high-birefringence photonic crystal fiber.

Abstract: Based on the nonlinear Schrödinger equations which can satisfy the optical pulses transmission in photonic crystal fiber, it is numerically simulated the pulse t rapping courses between the pump pulse in negative dispersion region and the signal pulse in positive dispersion region using step by step Fourier method, and the effect the nonlinear coefficient to the trapping course. The result shows if the nonlinear coefficient is small, the pulse trapping cant realize. Conversely, if the nonlinear coefficient increases, the cross phase modulation between the two pulses is enhanced and the frequency shifts are intensified too. When the group velocity is matched, the pulse trapping is realized. And the degree of trapping is strength accompany with the nonlinear coefficient increasing.

Abstract: The influence of grating period and length of Photonic Crystal Fiber Bragg Grating on delay is investigated by using numerical simulation method and the coupled mode theory. The result shows that grating length and period has remarkable impacts on the delay. The maximum value of the delay can be obtained by parameters optimization, which is 52ps occurs at the grating length of 1.06cm.

Abstract: This paper points out the properties of bismuth-based glass and the related design of photonic crystal fibers with flatted and normal group velocity dispersion profile. Supercontinuum generation in fiber is studied by a split-step Fourier numerical stimulation method. The results are shown for highly coherent mid-IR supercontinuum generation with 1.6 octaves bandwidth when pumping pulse width of 150fs and peak power of 40kW at 2.0μm. Analysis illustrates that supercontinuum generation dynamics are dominated by self-phase modulation and optical wave breaking.