Shubi Kaijage

Broadband Dispersion Compensating Octagonal Photonic Crystal Fiber for Optical Communication Applications

We numerically report the design of a modified octagonal photonic crystal fiber (M-OPCF) for broadband dispersion compensation covering the C and L communication bands, i.e., wavelengths ranging from 1530 to 1625 nm. It was shown that the proposed broadband compensating PCF can be designed to simultaneously exhibit a high negative dispersion coefficient and a relative dispersion slope (RDS) close to that of a conventional single-mode optical fiber (SMF). From our results, it was found that the M-OPCF has a large negative dispersion [-226 to -290 ps/(nmkm)] over the C- and L-bands, and an RDS close to that of an SMF of about 0.0034 nm-1. In addition to this, the effective dispersion, residual dispersion, confinement loss, and polarization properties of the proposed PCF are also reported and discussed.

Highly nonlinear dispersion-flattened square photonic crystal fibers with low confinement losses

A new simple structure of an index-guiding highly nonlinear dispersion-flattened square photonic crystal fiber (HNDFSPCF) with low confinement losses is proposed. The results reveal that it is possible to design five-rings HNDF-SPCFs with a flattened dispersion of 0.43 ps/(nm·km), low dispersion slope of -0:02 ps/(nm2·km), low confinement loss of approximately 103 dB/m, and a large nonlinear coefficient of approximately 35W-1 km-1 at 1.55 μm. It is also observed that the confinement loss is less than 10-1 dB/m in the wavelength range of 1.2 –1.7 μm.

Design of Highly Nonlinear Birefringent Photonic Crystal Fibers with Ultra-Flattened Chromatic Dispersion

We present a new cladding design for the photonic crystal fibers in order to achieve simultaneously high nonlinearity, dispersion-flattened characteristic, low confinement loss, and polarization maintaining properties. The finite difference method with anisotropic perfectly matched boundary layer is used as the numerical design tool. A nonlinear coefficient of the order 35 W-1 km-1 is obtained with a high birefringence of the order 1.5×10-4 at a 1550 nm wavelength. Ultra-flattened dispersion of 0±0.31 ps nm-1 km-1 is also obtained in a 1440 to 1600 nm wavelength range with low confinement losses less than 0.05 dB/m in the entire dispersion-flat band.

Highly nonlinear photonic crystal fiber with high refractive index core for dental OCT applications

Optical coherence tomography is a technology which supplies the tomographic image using the optical interference. It uses the 1.31 μm wavelength for dental applications. Resolution problems of such a technology can be improved by using supercontinuum light sources as low coherent broadband light is achievable from optical supercontinuum. Photonic crystal fibers have the ability to generate the supercontinuum light even with moderate input power levels. Only thing to consider is to ensure zero or nearly zero dispersion of such fibers at the target 1.31μm wavelength. This paper presents design of a high nonlinear photonic crystal fiber with near-zero dispersion around 1.31μm wavelength based on the finite difference method. Robustness of the design is confirmed numerically by generating wideband supercontinuum.

Chromatic Dispersion Properties of A Decagonal Photonic Crystal Fiber

This paper presents dispersion characteristics of a decagonal photonic crystal fiber (D-PCF) for the first time. The finite difference method (FDM) with an anisotropic perfectly matched boundary layer (PML) is used to investigate the chromatic dispersion characteristics. It is shown through numerical simulation results that D-PCFs can be used as a dispersion compensating fiber for their high negative dispersion slope characteristic. The dependency of chromatic dispersion with pitch, wavelength and air-hole diameters are also presented. Moreover, dispersion properties of D-PCF have been compared with that of the octagonal PCF (O-PCF) and hexagonal PCF (H-PCF), respectively.

Highly nonlinear photonic crystal fibers for optical coherence tomography applications

We propose a simple highly nonlinear photonic crystal fiber in optical coherence tomography window. Based on the finite difference method, different properties of highly nonlinear photonic crystal fibers are calculated. It is demonstrated that the nonlinear coefficients more than 64 and 55 [Wkm]−1 at 1.06 µm and 1.31 ??m, respectively, with flattened chromatic dispersion of 0 ± 3.7 ps/(nm.km) and low confinement losses less than 10−9 dB/m, simultaneously. It is also shown that small chromatic dispersion value and nearly zero dispersion slop provide the possibility of efficient supercontinuum generation in the optical coherence tomography window using a few ps pulses.

Decagonal Photonic Crystal Fibers with Ultra-Flattened Chromatic Dispersion and Low Confinement Loss

Decagonal PCFs with extremely low dispersion of 0 plusmn 0.26 ps/(nm-.km) in the wavelength range of 1.40 mum to 1.60 mum with confinement loss less than 10-6 dB/km is presented.

Highly nonlinear and polarization maintaining octagonal photonic crystal fiber in 1000nm regions

We propose a highly nonlinear polarization maintaining octagonal photonic crystal fiber possessing flattened dispersion properties within 0.98∼1.26 µm wavelength range. The PCF can be used for broadband supercontinuum generating light source in OCT medical applications.

An unique design of ultra-flattened dispersion photonic crystal fibers

We report that it is possible to control chromatic dispersion of photonic crystal fibers in wide wavelength range by using elliptical air-holes located at core disposed perpendicular alternately. Using this arrangement, a newly PCFs with ultra-low and ultra-flattened dispersion are designed with flattened dispersion of 0.23 [ps/km-nm] from 1.5 mum to 1.8 mum wavelength with the confinement loss less than 10-13 dB/m in the wavelength range shorter than 1.8 mum.

A novel ultra-flattened chromatic dispersion using defected elliptical pores photonic crystal fiber with low confinement losses

This paper reports a novel design in photonic crystal fiber (PCF) with nearly zero ultra flattened dispersion characteristics. We describe the chromatic dispersion controllability taking non-uniform air hole structures into consideration. Through optimizing non-uniform air hole structures, the ultra flattened zero dispersion PCF can be efficiently designed. We show numerically that the proposed triple non-uniform air cladding structure successfully achieves flat dispersion characteristics as well as extremely low confinement loss. As an example, the proposed PCF with flattened dispersion of plusmn0.28 ps/km/nm from 1.5 mum to 1.8 mum wavelength with extremely low confinement loss of less than 10-11 dB/m.