172 research outputs found
Mode-Field Radius of Photonic Crystal Fibers Expressed by the V-parameter
We numerically calculate the equivalent mode-field radius of the fundamental
mode in a photonic crystal fiber (PCF) and show that this is a function of the
V-parameter only and not the relative hole size. This dependency is similar to
what is found for graded-index standard fibers and we furthermore show that the
relation for the PCF can be excellently approximated with the same general
mathematical expression. This is to our knowledge the first semi-analytical
description of the mode-field radius of a PCF.Comment: Accepted for Opt. Let
Modal cut-off and the V-parameter in photonic crystal fibers
We address the long-standing unresolved problem concerning the V-parameter in
a photonic crystal fiber (PCF). Formulate the parameter appropriate for a
core-defect in a periodic structure we argue that the multi-mode cut-off occurs
at a wavelength lambda* which satisfies V_PCF(lambda*)=pi. Comparing to
numerics and recent cut-off calculations we confirm this result.Comment: 3 pages including 2 figures. Accepted for Optics Letter
The Creation of a Natural Church Development Coaching and Implementation Guide for the Seventh-day Adventist Church
The purpose of this dissertation is to answer some of the theological questions posed by the whole Natural Church Development, healthy church paradigm while at the same time developing a user-friendly, practical, Seventh-day-Adventist-sensitive implementation guide for use by local churches and coaches.https://digitalcommons.andrews.edu/hrsa/1006/thumbnail.jp
Low-loss photonic crystal fibers for transmission systems and their dispersion properties
We report on a single-mode photonic crystal fiber with attenuation and
effective area at 1550 nm of 0.48 dB/km and 130 square-micron, respectively.
This is, to our knowledge, the lowest loss reported for a PCF not made from VAD
prepared silica and at the same time the largest effective area for a low-loss
(< 1 dB/km) PCF. We briefly discuss the future applications of PCFs for data
transmission and show for the first time, both numerically and experimentally,
how the group velocity dispersion is related to the mode field diameterComment: 5 pages including 3 figures + 1 table. Accepted for Opt. Expres
Near-field to far-field transition of photonic crystal fibers: symmetries and interference phenomena
The transition from the near to the far field of the fundamental mode
radiating out of a photonic crystal fiber is investigated experimentally and
theoretically. It is observed that the hexagonal shape of the near field
rotates two times by pi/6 when moving into the far field, and eventually six
satellites form around a nearly gaussian far-field pattern. A semi-empirical
model is proposed, based on describing the near field as a sum of seven
gaussian distributions, which qualitatively explains all the observed phenomena
and quantitatively predicts the relative intensity of the six satellites in the
far field.Comment: 7 pages including 6 figures. Animated version of Fig. 5 is available
at http://www.crystal-fibre.com/technology/movie.gi
Photonic crystal fiber with a hybrid honeycomb cladding
We consider an air-silica honeycomb lattice and demonstrate a new approach to
the formation of a core defect. Typically, a high or low-index core is formed
by adding a high-index region or an additional air-hole (or other low-index
material) to the lattice, but here we discuss how a core defect can be formed
by manipulating the cladding region rather than the core region itself.
Germanium-doping of the honeycomb lattice has recently been suggested for the
formation of a photonic band-gap guiding silica-core and here we experimentally
demonstrate how an index-guiding silica-core can be formed by fluorine-doping
of the honeycomb lattice.Comment: 5 pages including 3 figures. Accepted for Optics Expres
Predicting macrobending loss for large-mode area photonic crystal fibers
We report on an easy-to-evaluate expression for the prediction of the
bend-loss for a large mode area photonic crystal fiber (PCF) with a triangular
air-hole lattice. The expression is based on a recently proposed formulation of
the V-parameter for a PCF and contains no free parameters. The validity of the
expression is verified experimentally for varying fiber parameters as well as
bend radius. The typical deviation between the position of the measured and the
predicted bend loss edge is within measurement uncertainty.Comment: Accepted for Optics Expres
Reduced micro-deformation attenuation in large-mode area photonic crystal fibers for visible applications
We consider large-mode area photonic crystal fibers for visible applications
where micro-deformation induced attenuation becomes a potential problem when
the effective area A_eff is sufficiently large compared to lambda^2. We argue
how a slight increase in fiber diameter D can be used in screening the
high-frequency components of the micro-deformation spectrum mechanically and we
confirm this experimentally for both 15 and 20 micron core fibers. For typical
bending-radii (R~16 cm) the operating band-width increases by ~3-400 nm to the
low-wavelength side.Comment: Accepted for Optics Letter
Single-mode photonic crystal fiber with an effective area of 600 square-micron and low bending loss
A single-mode all-silica photonic crystal fiber with an effective area of 600
square-micron and low bending loss is demonstrated. The fiber is characterized
in terms of attenuation, chromatic dispersion and modal properties.Comment: 10 pages including 3 figures. Accepted for Electronics Letter
- …