Realization of Optical CDMA Network Codecs Using Circulator-Free Fiber-Gratings Array

• Main Authors: Ming-Wei Kang, 康明煒
• Other Authors: Jen-Fa Huang
• Format: Others
• Language: en_US
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/45585846498893632083

碩士 === 國立成功大學 === 電機工程學系碩博士班 === 91 === 　　In this thesis, a realization technique of optical CDMA spectral-coding with fiber-Bragg-grating (FBG) -based codecs was proposed and experimentally demonstrated. Based on the modulation and detection principles that we have developed -- correlation subtractions of nearly orthogonal codes with balanced photo-detectors, this proposed FBG encoder/decoder configuration is much different from those published in the past. We introduce the transmissive spectral characteristics of FBGs to construct our FBG encoder/decoder. Instead, it provides several important advantages. First, the cost is lowered due to our circulator-free architecture. Second, the round-trip time problem is resolved. Besides, we also can reduce the power loss issue slightly. The testbed consists of two active encoders and three decoders. Both matched and unmatched cases are demonstrated. In order to counter the multiple-access-interference (MAI) effects caused by non-flattened optical sources, the spectral amplitude is sliced in the more flattened central region of broadband optical sources for partial compensation in our experiment. Our measurements verify that our proposed scheme is successful and practicable.