title: Approach to all-optical bipolar direct-sequence ultrawideband coding.
abstract: An approach to all-optical bipolar direct-sequence ultrawideband (UWB) encoding for multiple access communications is proposed and demonstrated. The bipolar coding is performed based on electro-optic phase modulation and phase modulation to intensity modulation (PM-IM) conversion in a fiber Bragg grating (FBG) array that serves as a multichannel frequency discriminator. The chip number and the chip period of the code are determined by the number of FBGs and their physical separation. By locating the optical carriers that carry a Gaussian pulse at the left or right slopes of the FBG reflection spectra, bipolar direct-sequence UWB codes are generated. A bipolar UWB coding system with a code length of 4 is experimentally demonstrated.
authors.affiliation: Microwave Photonics Research Laboratory, School of Information Technology and Engineering, University of Ottawa, ON K1N 6N5, Canada.
authors.forename: Qing
authors.initials: Q
authors.lastname: Wang
authors.forename: Jianping
authors.initials: J
authors.lastname: Yao