Waveguides with low confinement loss, low chromatic dispersion, and low nonlinear effects are used in Optical communication systems. Optical fibers can also be employed in such systems. Besides Optical fibers, photonic crystal fibers are also highly suitable transmission media for Optical communication systems. In this paper, we introduce two new designs of index-guiding photonic crystal fiber (IGPCF) with characteristics appropriate for Optical Communications. In the first proposed design with a hexagonal structure having a defect at the center, the chromatic dispersion at the wavelength of 1550 nm is less than 1 ps/(nm. km). In the second design with a hexagonal structure having air holes with unequal diameters, nearly zero dispersion at the wavelength range of 1370 to 1380 nm is achieved. At the same time, for the latter design, at the wavelength of 1550 nm, the chromatic dispersion slope is 1 ps/(km. nm), the confinement loss is less than 10􀀀 9 dB/km, and the nonlinear coefficient reaches 3. 690 W􀀀 1. km􀀀 1.

Research on wireless Communications using the Optical spectrum has made great progress over the past few decades and has been standardized under the IEEE 802.15.7 standard for visible light communication (VLC) systems. In 2018, this standard was upgraded and named IEEE 802.15.7-2018. In addition, wireless communication systems using image sensors or cameras, which are integrated into smart mobile devices, are added, called Optical camera communication (OCC). In this article, we showed the implementation perspective on Optical Camera Communication (OCC) technologies within the latest international OCC standard. The performance evaluation of various OCC schemes are provided through extensive simulations and practical implementation results. This contributes as supporting material to promote the standard into real-life use cases and deliver helpful guidelines for OCC implementers. Moreover, demonstrations of several advanced modulations and coding schemes for OCC are also given and compared with existing standard OCC schemes for discussing possible research directions in the future.

Visible Light Communication (VLC) has emerged as a powerful technique for wireless communication systems. Providing high data rate and increasing capacity are the major problems in VLC. Recent evidence suggests that Multiple Input Multiple Output (MIMO) technique can offers improved data rates and increased link range. This paper describes the design and implementation of visible light communication system in indoor environment exploring the benefits of MIMO. The specific objective of this research was to implement a 4×4 Multiple Input (LEDs) Multiple Output (photodetectors)-VLC communication system, where a 16 white power LEDs in four arrays are setting up at transmitter and four RX modules are setting up at receiver side without the need for additional power or bandwidth as well as analyze a mathematical model for a VLC-×4 MIMO with different modes such as the suitable angles to cover the entire room. The research designs practically an electronic circuit for the transmitter and receiver with inexpensive components. The power distribution of different propagation modes is calculated for Single Input Single Output (SISO) and MIMO channels in typical room dimensions. The results in this paper indicate that the power is distributed uniformly for entire room when implemented VLC-MIMO as compared to VLC-SISO. Furthermore, a 4×4 MIMO implementing VLC is compared in term of BER vs. SINR with SISO communication system for both Line of Sight (LOS) and Non Line of Sight (NLOS) propagation modes. Comparing the two results of LOS and NLOS, it can be seen that a 4×4 MIMO implementing VLC for LOS perform better than the same system with NLOS due to decreasing in the received power resulted from the multipath effect.

To mitigate the high peak-to-average power ratio (PAPR) of discrete multi-tone (DMT) modulation in polymer Optical fibers (POF) communication systems, a novel DMT scheme based on Jacket matrix spreading (JS) is proposed. Approximations of PAPR distribution for DMT signals are accurately presented. Single band JS-DMT and multi-band (MB)-JS-DMT are introduced in POF transmission link for PAPR reduction. Offline processing and simulations are adopted to investigate the performance of these new schemes with regard to the PAPR reduction, power spectral density (PSD), data rate and bit error rate (BER). The results demonstrate that, applying the JS methodology, up to 4dB PAPR reduction is achieved. JS-DMT is sensitive to the bandwidth range whereas MB-JS-DMT owns the robustness ability against fiber nonlinearity. Compared with some well known PAPR reduction techniques, the proposed schemes can be easily applied to the DMT modem and achieve the PAPR reduction efficiently without degrading the BER, data rate and PSD performance, which demonstrate the feasibility and validity of these two methods in POF transmission.

We numerically analyzed the photonic band structure of 2-D metallic-dielectric photonic crystal structures which consist of square arrays with circular metal rods. We calculated dispersion curves of square lattice with metal rods which are embedded into background materials with different dielectric constants for TM and TE modes and changed the ratio of the rods’ radius to the lattice constant (r/a).We also investigated the effect of changing metal rods on the photonic band structures in two steps. In the first step, we changed background materials with fixed r/a constant and then we fixed both ther/aratio and background dielectricconstants. Because we designed our structure in a way that the photonic band gaps appear in a range of telecommunication wavelength the results showed that these structures will be applicable in different photonic devices such as Optical filters.