Steady the distortion of the transmitting data due to the spectral shift effect of semiconductor laser with increasing of frequency in optical communication systems

In this study, a semiconductor laser (also called laser diode (LD)), light emitting diode (LED) and Polymers Light-Emitting diode (PLED) have been studied in Steady the Distortion of the Transmitting Data due to the Spectral Shift Effect of Semiconductor Laser with increasing of Frequency in optical Communication Systems of the central wavelength and spectral width effected by increasing of frequency that casus the increase in temperature in light sources, where the increasing of frequency is very important in communication system that utilized to rise the data transmission bandwidth. We had designed an oscillation circuit to generate a narrow light pulse to simulate the transmission system. The different frequencies (10, 100, 10000, 100000 and 500000) Hz has been used for small pulse width (100, 500 and 1000) ns. The experimental test show that all optical sources suffer from a dispersion of spectrum in the beam and a visual red shift. This is more in LD and less in LED. The spectrum broadening is bad phenomena in optical communication systems that lead to losing of data due to saturation in spectrum of sources when light transfer through different medium. The results show that the LED is the best choice for data transmission which is very stable than LD and PLED that suffer from red shifting, in addition to subject spectrum broadening that cased by difference in transferring speed when passes in different medium cases interference and losses of data. Even so the LED has a disadvantage that it low in power which cannot be transmitting for long distance where the LD is best choice for free space optical communication system (FSO), while LED is best in optical fiber communication system.