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Proceedings Paper

A grating-based 40 Gb/s OCDM coding-decoding system
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Paper Abstract

A 7-chip, 280-Gchip/s quaternary phase-shift code is assigned to short pulses after reflection from a encoder, The code is then recognized by a decoder. The encoder and decoder used within our experiments are 4-phase shift SSFBGs. Each grating containing 7-chip has a uniform amplitude refractive index level along its length but in which discrete jumps in phase (0,∏/2,∏,or 3∏/2) are written into the grating at the boundaries of adjacent spatial chips. The 4-phase shift SSFBGs were fabricated using "equivalent phase shift" method, wherein the desired phase shift in one channel of Sampled Bragg grating (SBG) could be achieved by simply changing the sampling period. Only ordinary phase masks and submicrometer precision are needed to fabricate the encoding and decoding SSFBGs. The quaternary phase encoding and decoding of short pulses at 40Gb/s is experimentally demonstrated, to the authors' knowledge, this is the highest single channel rate obtained from FBG based OCDM system. Multiple user interference (MUI) is also considered and evaluated, we present an experimental demonstration 2-user 40Gb/s/user (2×40Gb/s) OCDM system employing 4-phase pulse pattern generation and recognition. In addition, a nonlinear optical loop mirror (NOLM) within the receiver is introduced to improve the system performance under multiuser operation, we show that the NOLM can act as a nonlinear processing element capable of reducing both the pedestal associated with conventional matched filtering and the width of the associated code recognition pulse. The system benefits of using the NOLM are experimentally demonstrated under 2-user operation.

Paper Details

Date Published: 9 December 2005
PDF: 8 pages
Proc. SPIE 6021, Optical Transmission, Switching, and Subsystems III, 60212I (9 December 2005); doi: 10.1117/12.633472
Show Author Affiliations
Xiaogang Chen, Huazhong Univ. of Science and Technology (China)
Dexiu Huang, Huazhong Univ. of Science and Technology (China)
Xiuhua Yuan, Huazhong Univ. of Science and Technology (China)

Published in SPIE Proceedings Vol. 6021:
Optical Transmission, Switching, and Subsystems III
Rodney S. Tucker; Dominique Chiaroni; Wanyi Gu; Ken-ichi Kitayama, Editor(s)

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