Fiber Bragg Gratings for MAI-Immuned Optical CDMA Communications

• Main Authors: Cheng-Yuan Hsieh, 謝長原
• Other Authors: Jen-Fa Huang
• Format: Others
• Language: en_US
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/04592358781990743544

碩士 === 國立成功大學 === 電機工程學系 === 88 === With the significant discovery of photosensitivity in optical fibers, a new class of in-fiber component has been developed, called the fiber Bragg grating (FBG). The fiber Bragg gratings have many advantages, such as low loss transmission, immunity to electromagnetic interference, easy fabrication, make the intro-core grating an ideal candidate for use in telecommunications and sensory field. Fiber Bragg gratings are proposed as coding devices for optical code-division multiple-access (OCDMA) systems. Fiber Bragg gratings will spectrally slice incoming broadband optical spectrum into several spectral chips. With properly written CDMA coding pattern, the reflected light field from FBG is spectrally encoded onto an address code. Each central wavelength of sliced chips is different to each other and will distribute over the spectrum of the incoming light source. By assigning the N cycle shifts of a signal m-sequence to N users, we get an OCDMA network that can support N simultaneous users. The multiple-access interference (MAI) has been shown to limit the performance of optical CDMA system. We will show the optical CDMA with its encoder and decoder based on the fiber Bragg gratings. We will do a simple experiment to show the effect of MAI and finally we will try to compensate the effect of MAI.