الفهرس 
IntroductionOnly 14 pages are availabe for public view
 |  | from | 133 |  |  |
| | | from | 133 | | |
Abstract
There has been a tremendous interest in applying spread spectrum and code division multiple access (CDMA) techniques to optical communication systems. In this dissertation, the previous work on optical CDMA systems is reviewed, also, the most common passive optical components usually used in the implementation of such systems. The explosive growth in band width demand during the recent years have compelled engineers to achieve efficient utilization of bandwidth in optical links. It is pointed out that in order to achieve this , full orthogonality is required in optical CDMA and so the effects of signature codes on some type of OCDMA systems should be considered . The optical Code division multiple access with pulse position modulation (OCDMA-PPM) communication systems are studied considering the effects of using new types of channel codes with it , and here, new types of channel codes are proposed to improve the bit error probability. Finally, a new structure of fast frequency hopping OCDMA (FFH-OCDMA) based on using the cheapest optical components ,(double ion exchange diffraction grating and optical delay lines) is proposed and demonstrated. The resulted system overcomes the disadvantages of the FBG (Fiber bragg grating) based system previously proposed and has many magnificent features over many OCDMA systems. Key words: optical communications , CDMA systems.