Holey Optical Fibers Research Articles

Generation of random-hole optical fiber.

A new form of holey optical fiber, the random-hole optical fiber, has been devised. The hole structure is produced by generating bubbles in a powdered silica cladding. The bubbles are then drawn into tubules of random size, location, and length during the fiber-draw process. Although the tubes are not continuous along the length of the fiber, as has been the case in previous holey fibers, the tubes are very long, and the average number of holes in any cross section is large. Waveguide losses of approximately 1.55 dB/m have been measured.

Boundary element method for analysis of Holey optical fibers

By using a full-vector boundary element method (BEM) based on a formulation in terms of transverse magnetic field components, holey fibers (HFs) are numerically analyzed. The BEM provides very accurate solutions with an extremely small number of unknowns. Not only the characteristics of all-silica HFs, but also those of hole-assisted lightguide fibers and field-confined HFs, are investigated and compared with each other.

Opposite-parity orthonormal function expansion for efficient full-vectorial modeling of holey optical fibers.

An improved full-vectorial method exploiting the opposite-parity property of eigenmodes based on orthonormal-functions expansion is proposed to solve the wave equation for holey optical fibers. By use of the parity property of eigenmodes in symmetric structures, the number of orthonormal function integrals involved in the calculation is reduced, and the computation efficiency is greatly enhanced. The coupling between the two transverse field components is considered, and both dominant and minor field components can be calculated for the accurate modeling of fiber modes. This method is useful for efficiently modeling holey fibers, especially those with large air holes, in which the coupling effect that is due to refractive-index discontinuities is strong.

Homogenization expansion for resonances of microstructured photonic waveguides

We develop a homogenization expansion approach to photonic waveguides whose transverse structures are N-fold rotationally symmetric. Examples include microstructured or holey optical fibers with air holes arranged in one or more concentric rings. We carry out a homogenization expansion for large N about the N=∞ limit. Our multiple scale analysis applies to the scalar approximation of structures in which the microfeatures have arbitrary geometry and large index contrasts and lead to a natural efficient computational algorithm for the waveguide modes and spectral characteristics. In this paper we focus on structures that possess leaky modes. The leading order (N=∞) equations describe the modes of an averaged structure. We derive an expansion in powers of 1/N of corrections to the leading order behavior and show that the leading order nontrivial contribution arises at order 1/N2. We numerically calculate this leading order correction to the complex effective indices (scattering resonances) for the leaky modes of various microstructured photonic waveguides whose imaginary parts give the leakage rates. We observe that in many instances a two-term truncation of the homogenization expansion gives good agreement with full simulations, even for fairly small values of N, whereas the leading order (averaged) theory yields a substantial underestimate of the leakage rates.

Phase sensitivity of conventional single-mode and holey optical fibers: a comparison study

A comparison of phase sensitivity is conducted for two different types of optical fiber designs with the same outer diameter. The optical fibers are subjected to a hydrostatic pressure load. The finite element model validates well with the analytical solutions. The holey fiber selected for this study showed a 130% phase sensitivity gain over a conventional single-mode optical fiber due to its hollow structure, enabling the external pressure load to strain the core beyond that observed in solid optical fibers. The holey fiber's outer coating also enhances the phase sensitivity, with improved performance over conventional single-mode optical fibers with the same coating.

Investigation of Brillouin effects in small-core holey optical fiber: lasing and scattering

We demonstrate for what is believed to be the first time a Brillouin laser based on a holey fiber (HF). Using a simple Fabry-Perot resonator scheme containing a 73.5-m-long highly nonlinear HF with an effective area of 2.85 microm(2) , we obtain a threshold of 125 mW and a slope efficiency of ~70% . Stimulated and spontaneous Brillouin scattering effects are investigated in the HF, and we show that the high lasing threshold is due mainly to reduction of the effective gain coefficient caused by structural nonuniformity along the fiber length.

Broad-band second-harmonic generation in holey optical fibers

Holey fibers are shown to have an ideal geometry for efficient parametric processes due to their tailorable modal properties. These fibers can have the additional advantage of single-mode operation at all the interacting wavelengths. We demonstrate theoretically that by appropriate choice of holey fiber geometry, these fibers can be up to four orders of magnitude more efficient for second harmonic generation than conventional poled fibers.

Splice losses in holey optical fibers

Splice losses between standard step-index fiber and holey optical fibers were calculated for a range of fiber parameters and wavelengths using finite-difference time-domain simulations. The optimal holey fiber parameters for minimum splice loss were determined. It was found that the optimal parameters could also be predicted using analytical approximations incorporating the effective index model.

Modeling large air fraction holey optical fibers

We develop a modal decomposition approach to solve the full vector wave equation for holey optical fibers (HF). This model can be used to explore the modal properties of a wide range of HFs, including those with large air holes. The optical properties of HF can be tailored via the arrangement of the air holes, and this flexibility leads to a wide range of practical applications.

Nonlinearity in holey optical fibers:?measurement and future opportunities—errata

Nonlinearity in holey optical fibers:?measurement and future opportunities—errata

Nonlinearity in holey optical fibers: measurement and future opportunities

Holey fibers combine two-dimensional microstructuring with one-dimensional longitudinal propagation, resulting in fibers with tailorable dispersive and nonlinear properties. We measure the effective nonlinearity of a typical holey fiber. The small effective area that is possible in this type of fiber significantly enhances its effective nonlinearity relative to standard fiber.

Waveguiding properties of holey fibres and effective-Vmodel

The authors examine the waveguiding properties of holey optical fibres made with circular silica tubes. The effective index of the fundamental mode and the first higher-order mode cutoff wavelength have been obtained for different fibres. The effective-V model is found to be unsuitable in describing the guiding properties of such fibres.

Holey optical fibers: an efficient modal model

A new model for light propagation in holey optical fibers is developed in which the transverse index profile and the modal field are decomposed using different orthogonal functions. It is an efficient and accurate alternative to previous techniques, and is an invaluable tool to aid fabrication efforts. Using this model, a number of regimes of interest in these fibers are explored.