Characteristics of Ultrasensitive Hexagonal-Cored Photonic Crystal Fiber for Hazardous Chemical Sensing

A highly sensitive non-complex cored photonic crystal fiber sensor for hazardous chemical sensing with water, ethanol, and benzene analytes has been proposed and is numerically analyzed using a full-vector finite element method. The proposed fiber consists of a hexagonal core hole and two cladding air hole rings, operating in the lower operating wavelength of 0.8 to 2.6 µm. It has been shown that the structure has high relative sensitivity of 94.47% for water, 96.32% for ethanol and 99.63% for benzene, and low confinement losses of 7.31 × 10−9 dB/m for water, 3.70 × 10−10 dB/m ethanol and 1.76 × 10−13 dB/m benzene. It also displays a high power fraction and almost flattened chromatic dispersion. The results demonstrate the applicability of the proposed fiber design for chemical sensing applications.

CHROMATIC DISPERSION COMPENSATION IN EXISTING FIBER OPTIC TELECOMMUNICATION LINES WITH THE GROWING BIT RATES NEEDS OF DWDM SYSTEM

The article presents an analysis of the methods of chromatic dispersion compensation in the existing, already built fiber optic telecommunications lines, based on ITU G.652 A and B fibers with the constantly growing demand for bit rates in DWDM systems. Due to the enormous investment costs, it is impossible to replace the cables used with NZDSF, hence the chapter analyzes methods of improving the bandwidth without replacing all cables. Typical models of the optimization of chromatic dispersion in the existing lines are presented.

Comparison of RZ and NRZ Modulation Techniques by Varying Duty Cycle and Mach Zehnder Modulator

The aim of the research being undertaken is to examine the performance of advanced modulation formats such as RD and NRZ modulation schemes and their long-haul repeater-free fibre-traffic (SMF). Modular transmission of signals by SMF has been highly attracted by several benefits, such as high chromatic dispersion tolerance (CD), simplicity of deployment and higher spectrum efficiencies. These are the essential performance indicators of an optimal modulation technique for the creation of multiplexed (DWDM) transmission networks of the future generation of dense wavelengths. Based on a comparison of the two modulation approaches I give my findings. To mimic both modulation schemes, OptiSystem software is employed. Eye diagram with measurement of the Q factor and BER is generated. Keywords: Return to Zero, Non-Return to Zero, Eye Diagram, Bandwidth, BER, Q factor.