Photonic-Crystal Fibres with Suspended Core - Numerical Analyses

Abstract

The paper gives a short description of light guidance mechanisms of index-guided photonic-crystal fibres. The results of numerical analyses of photonic-crystal fibres with a suspended core are presented. Such fibres are planned to be applied for investigation of magneto-optic effects in gaseous media.

Focusing with 2D Square Photonic Crystal with Concavo-Concavo Boundaries

“…1b). When light travels through interference between a homogeneous medium and a PhC structure, Bloch modes are excited, whose directions can be determined by means of EFC [3][4][5]. EFC is transformation of coordinates from band diagram (frequency versus wave vector) to isofrequency contours which consist of all allowed propagation modes in wave vector space that exist in the PhC structure for a certain frequency [3].…”

“…2. To enhance focusing we removed a set of holes from both sides of the PhC to create concavo-concavo boundaries with radius R1 and R2 [5]. We also used two antireflective layers to improve coupling of light between air/silicon interfaces.…”

Evolution of the diffraction pattern during the transition from the near-field toward the far-field region

“…In such a case light is strongly confined in the core and just fractionally penetrates the air channels as * e-mail: pustelny@uj.edu.pl 1 Note that on the most fundamental level the fraction of light present in the fiber channels depends on the refractive-index contrast between fiber material and filling medium evanescent field. Despite the relatively low air-channels filling factor [24], the fibers are very promising for chemical and biological sensing due to their guidance of spectrally broad light (index guiding) and easiness in filling the air channels (see [11] and references therein).…”

Hollow-Core Bragg Fiber for Bio-Sensing Applications

“…In the case of PBG light is propagating in a core with the refractive index that is smaller than the refractive index of the cladding thanks to the Bragg reflection. A very first photonic band gap optical fiber presented by Yeh in 1978 was the Bragg fiber [1][2][3]. Cladding of the Bragg fiber is composed of concentric circular layers with alternately higher and lower refractive indices.…”