78,698 research outputs found
Photonic Crystal and Photonic Crystal Fibers Communications
The development of all optical communications could benefit from the index guiding photonic crystal fibers. In communication the photonic crystal fibers could provide many new solutions. Conventional optical fibers have within the last decades revolutionized the communications industry and it is today a mature technology being pushed to its limit with respect to properties such as losses, single mode operation and dispersion. The spectra have been used by others to develop optical frequency standards. The process can potentially be used for frequency conversion in fiber optic network. In this system the dispersive properties can be controlled by the optical lattice making it possible to achieve phase-matched four wave mixing, like look the process taking place in the photonic crystal fibers. In this paper we will discuss the use of photonic crystal fibers in communications
Efficient excitation of self-collimated beams and single Bloch modes in planar photonic crystals
Using finite-difference time-domain calculations, we investigate out-of-plane coupling between a square-lattice
planar photonic crystal and a conventional waveguide located above the photonic crystal. We couple a waveguide
oriented in the GX direction to a photonic crystal mode in the second band and show that anticrossing takes place. In this way, a self-collimated beam is launched in the planar photonic crystal, with full power transfer. Furthermore, we investigate the coupling between a waveguide oriented in the GM direction and a photonic crystal and show that single photonic crystal modes can be selectively excited
Propagation of Light in Photonic Crystal Fibre Devices
We describe a semi-analytical approach for three-dimensional analysis of
photonic crystal fibre devices. The approach relies on modal transmission-line
theory. We offer two examples illustrating the utilization of this approach in
photonic crystal fibres: the verification of the coupling action in a photonic
crystal fibre coupler and the modal reflectivity in a photonic crystal fibre
distributed Bragg reflector.Comment: 15 pages including 7 figures. Accepted for J. Opt. A: Pure Appl. Op
Graphene-based photonic crystal
A novel type of photonic crystal formed by embedding a periodic array of
constituent stacks of alternating graphene and dielectric discs into a
background dielectric medium is proposed. The photonic band structure and
transmittance of such photonic crystal are calculated. The graphene-based
photonic crystals can be used effectively as the frequency filters and
waveguides for the far infrared region of electromagnetic spectrum. Due to
substantial suppression of absorption of low-frequency radiation in doped
graphene the damping and skin effect in the photonic crystal are also
suppressed. The advantages of the graphene-based photonic crystal are
discussed.Comment: 4 pages, 3 figure
Photonic Crystal Laser Accelerator Structures
Photonic crystals have great potential for use as laser-driven accelerator
structures. A photonic crystal is a dielectric structure arranged in a periodic
geometry. Like a crystalline solid with its electronic band structure, the
modes of a photonic crystal lie in a set of allowed photonic bands. Similarly,
it is possible for a photonic crystal to exhibit one or more photonic band
gaps, with frequencies in the gap unable to propagate in the crystal. Thus
photonic crystals can confine an optical mode in an all-dielectric structure,
eliminating the need for metals and their characteristic losses at optical
frequencies.
We discuss several geometries of photonic crystal accelerator structures.
Photonic crystal fibers (PCFs) are optical fibers which can confine a
speed-of-light optical mode in vacuum. Planar structures, both two- and
three-dimensional, can also confine such a mode, and have the additional
advantage that they can be manufactured using common microfabrication
techniques such as those used for integrated circuits. This allows for a
variety of possible materials, so that dielectrics with desirable optical and
radiation-hardness properties can be chosen. We discuss examples of simulated
photonic crystal structures to demonstrate the scaling laws and trade-offs
involved, and touch on potential fabrication processes.Comment: 3 pages, 3 figures; Submitted to Particale Accelerator Conference
(PAC 2003), May 12-16, 2003, Portland, Oregon (IEEE
Degeneracy analysis for a super cell of a photonic crystal and its application to the creation of band gaps
A method is introduced to analyze the degeneracy properties of the band
structure of a photonic crystal making use of the super cells. The band
structure associated with a super cell of a photonic crystal has degeneracies
at the edge of the Brillouin zone if the photonic crystal has some kind of
point group symmetry. Both E-polarization and H-polarization cases have the
same degeneracies for a 2-dimensional (2D) photonic crystal. Two theorems are
given and proved. These degeneracies can be lifted to create photonic band gaps
by changing the transform matrix between the super cell and the smallest unit
cell. The existence of the photonic band gaps for many known 2D photonic
crystals is explained through the degeneracy analysis.Comment: 19 pages, revtex4, 14 figures, p
Continuous-wave operation of electrically pumped, single-mode, edge-emitting photonic crystal Bragg lasers
The authors demonstrate an electrically pumped, single-mode, large-area, edge-emitting InGaAsP/InP two dimensional photonic crystal Bragg laser operating in continuous-wave condition. The laser uses a weak index perturbed, polymer-planarized, surface photonic crystal structure to control the optical mode in the wafer plane. They find that the laser operates in single transverse and longitudinal modes. They compare the performance of the photonic crystal Bragg laser with a broad-area laser fabricated from the same wafer and the comparison shows that the performance penalty incurred by the photonic crystal is small
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