Demonstration of 10 Gbit/s-Based Time-Spreading and Wavelength-Hopping Optical-Code-Division-Multiplexing Using Fiber-Bragg-Grating En/Decoder

Naoki MINATO
Hideaki TAMAI
Hideyuki IWAMURA
Satoko KUTSUZAWA
Shuko KOBAYASHI
Kensuke SASAKI
Akihiko NISHIKI

Publication
IEICE TRANSACTIONS on Communications   Vol.E88-B    No.10    pp.3848-3854
Publication Date: 2005/10/01
Online ISSN: 
DOI: 10.1093/ietcom/e88-b.10.3848
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Next Generation Photonic Network Technologies)
Category: 
Keyword: 
optical fiber communications,  optical code division multiplexing (OCDM),  fiber Bragg grating (FBG),  dispersion compensation,  

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Summary: 
We studied 10 Gbit/s-based time-spreading and wave-length-hopping (TS-WH) optical code division multiplexing (OCDM) using fiber Bragg gratings (FBGs). To apply it to such the high bit rate system more than ten gigabit, two techniques are adopted. One is encoding with the maximum spreading time of 400 ps, which is four times as data bit duration, to encode without shortening chip duration. Another is encoder design. The apodized refractive index profile to the unit-gratings composing the encoder is designed to encode the pulses with 10-20 ps width at 10 Gbit/s rate. Using these techniques, 210 Gbit/s OCDM is demonstrated successfully. In this scheme, transmission distance is limited due to dispersion effect because the signal has wide bandwidth to assign a wavelength-hopping pattern. We use no additional devices to compensate the dispersion, in order to construct simple and cost-effective system. Novel FBG encoder is designed to incorporate both encoding and compensating of group delay among chip pulses within one device. We confirm the extension of transmission distance in the TS-WH OCDM from the demonstration over 40 km-long single mode fiber.