Nonlinear spectrum distortions are caused by the peculiarities of the operation of charge-coupled device elements (CCD), in which the signal exposition time (Time of INTegration–TINT) is one of the significant parameters. A change of TINT on a CCD leads to a nonlinear distortion of the resulting spectrum. A nonlinear distortion of the spectrum, in turn, leads to errors in determining the central wavelength of fiber Bragg gratings (FBGs) and spectrally sensitive sensors, which, in general, negatively affects the accuracy of the measuring systems. This paper proposes an algorithm for correcting the nonlinear distortions of the spectrum obtained on a spectrum analyzer using CCD as a receiver. It is shown that preliminary calibration of the optical spectrum analyzer with subsequent mathematical processing of the signal makes it possible to make corrections in the resulting spectrum, thereby leveling the errors caused by measurements at different TINT.

In the present work the future communication requirements need to fulfill with high data rate, FSO (free space optic) with it is tremendous potential is the solution. This research observed the effectiveness analysis of FSO systems by modifying one of the most important FSO parameters beam divergence, under the most affected weather attenuating condition Rainwater and snow pack. The simulation is obtained and analyzed under single channels CSRZ-FSO (carrier-suppressed return-to-zero/free space optical) systems having capacity of 40 Gbps between two transceivers with variable distance. The connection is presently under 5 meteorological turbulences (light rain, medium rain, wet snow, heavy rain and dry snow). The results show the heavy rain and dry snow have a very high attenuation carried out in terms of Q-factor. this result led us to conclude that small divergence offers significant performance improvement for FSO link and this performance decrease every time the beam divergence increase, Therefore, to build inexpensive and reliable transmission media, we go with new method that still in the experiment area called hybrid RF/FSO (radio frequency/free space optical) that compatible with atmospherically status.

The require a bandwidth of every person will be increased from 16 Mbit/s to 50 up to 100M bit/s in the next 5 years in most of the growing counties. To solve this problem, FTTH may be the appropriate solution in a wide range. We experimentally investigate the deploy of PON-FTTH based on different kinds of passive optical network technology (E-PON, G-PON and VCSEL) and study the Obstacles of PON-FTTH Immigration after comparing it with older service (XDSL). Then analysis the reason on why these technologies chose by some country not others and why the technological need in Europe different with need in Africa and America. We discussed the solutions in telecommunications networks and or the economic aspect of projects all over the world, we found that GPON is more appropriable for accomplishment PON-FTTH than other networks. Thus GPON has been chosen for Europe, America and middle east. Choosing GPON techniques is decided by many factors include the infrastructure that was made before, the people demand for service and how much service they need because the need in Europe different with need in Africa and American and so on. Finally, we will suggest the appropriate solution in the energy savings, cost effective, higher security, and side of service transparency over other access networks for the future demand.

Nonlinear spectrum distortions are caused by the peculiarities of the operation of charge-coupled device elements (CCD), in which the signal exposition time (TINT) is one of the significant parameters. A change of TINT on a CCD leads to a nonlinear distortion of the resulting spectrum. Nonlinear distortion of the spectrum, in its turn, leads to errors in determining the central wavelength of Fiber Bragg Gratings (FBG) and spectrally sensitive sensors, which, in general, negatively affects the accuracy of measuring systems. The paper proposes an algorithm for correcting nonlinear distortions of the spectrum obtained on a spectrum analyzer using CCD as a receiver. It is shown that preliminary calibration of the optical spectrum analyzer with subsequent mathematical processing of the signal makes it possible to make corrections in the resulting spectrum, thereby leveling the errors caused by measurements at different TINT.

Downstream Performance Analysis and Optimization of 2.5 Gbit/sec GPON-FTTX using NRZ and RZ Modulation Formats