Optical Properties of Photonic Crystal Fibers With a Fiber Core of Arrays of Subwavelength Circular Air Holes: Birefringence and Dispersion

Abstract

Abstract-We propose a kind of novel photonic crystal fibers (PCFs) based on a fiber core with arrays of subwavelength circular air holes, achieving the flexible control of the birefringence or the dispersion property of the PCFs. A highly birefringent (HB) PCF is achieved by employing arrays of subwavelength circular air hole pairs in the fiber core, which are arranged as a conventional hexagonal lattice structure with a subwavelength lattice constant. The HB-PCF is with uniform and ultrahigh birefringence (up to the order of 0.01) in a wavelength region from 1.25 µm to 1.75 µm or even a larger region, which, to the best of our knowledge, is the best birefringence property of the PCFs. A dispersion-flattened (DF) PCF with near-zero dispersion is achieved by employing arrays of subwavelength circular air holes in the fiber core arranged as a conventional hexagonal lattice structure with a subwavelength lattice constant, which contributes negative waveguide dispersion to the PCF. The proposed design of the DF-PCF provides an alternate approach for the dispersion control of the PCF. Besides the high birefringence and the flattened near-zero dispersion, the proposed PCFs with a fiber core of arrays of subwavelength circular air holes have the potential to achieve a large mode area single mode PCF.

Fourier Based Combined Techniques to Design Novel Sub-Wavelength Optical Integrated Devices

“…If the period length Λ is shorter than the shortest Bragg period, the stratified structure behaves as a homogeneous medium [1]. Note that, even when the constituent materials are isotropic, the refractive index of the equivalent homogeneous medium depends on the incident field polarization, which can be used to engineer the birefringence [16]. That refractive index can be expressed with the zeroth-order approximation [1] …”

Single-Nanoweb Suspended Twin-Core Fiber for Optical Switching

“…However, much of the optical switches are still predominantly performed electrically in recent applications. With the emergence and development of the microstructure fiber (MSF) which has shown a great success to achieve unique properties such as high birefringence [28][29][30][31][32][33][34][35][36], flattened dispersion [37][38][39][40], large negative dispersion [41,42], high nonlinearity [43,44], endless single mode [45] and so on, there emerges a new opportunity for the exploration of optical switching technology that it is possible to make the optical fiber be an optical switch. Recently, a type of nanomechanical optical fiber [46] has been proposed and demonstrated, which has two fiber cores independently suspended within the fiber.…”

Highly Birefringent Four-Hole Fiber for Pressure Sensing

“…More recently, several microstructured fibers (MSFs) (i.e., photonic crystal fibers (PCFs)) were also proposed for pressure sensing [13][14][15][16][17][18][19][20][21][22]. Thanks to the design flexibility of the cross-section, MSFs have achieved excellent properties in birefringence [23][24][25][26][27][28][29], dispersion [30][31][32][33][34], single polarization single mode [35][36][37], nonlinearity [38], and effective mode area [39][40][41] over the past several years. MSFs have shown some advantages for applications in optical fiber sensors, such as temperature insensitivity for strain sensing, high sensitivity for pressure sensing and so on.…”