OCDMA over WDM PON-solution path to gigabit-symmetric FTTH

• Published in: Journal of lightwave technology 2006-04, Vol.24 (4), p.1654-1662
• Main Authors: Kitayama, K., Xu Wang, Naoya Wada
• Format: Article
• Language: English
• Subjects: Applied sciences; Architecture; Coding, codes; Computer networks; Crosstalk; Decoders; Decoding; Downlink; Exact sciences and technology; Gigabit; Information, signal and communications theory; Multiaccess communication; Multiple access; Multiplexing; optical code-division multiple access (OCDMA); Optical crosstalk; Optical design; Optical fiber communications; Optical fiber subscriber loops; Optical fibers; Optical telecommunications; passive optical network (PON); Passive optical networks; Reflection; Signal and communications theory; Studies; System performance; Systems, networks and services of telecommunications; Telecommunications; Telecommunications and information theory; time-division multiplexing (TDM); Transmission and modulation (techniques and equipments); Wavelength division multiplexing; wavelength-division multiplexing (WDM); WDM networks
• ISSN: 0733-8724; 1558-2213
• DOI: 10.1109/JLT.2006.871030

It will be revealed that a myth of deploying low bit-rate uplink fiber-to-the-home (FTTH) services while providing a high bit-rate downlink is wrong. Therefore, for the future broadband FTTH services, the focus should be on the capability to provide gigabit- or even multigigabits-per-second both in up- and downlinks, namely gigabit symmetric systems. Optical code-division multiple access (OCDMA) now deserves a revisit as a powerful alternative to time-division multiple access and wavelength-division multiple (WDM) access in FTTH systems. In this paper, the authors will first highlight the OCDMA systems. The system architecture and its operation principle, code design, optical en/decoding, using a long superstructured fiber Bragg grating (SSFBG) en/decoder, and its system performance will be described. Next, an OCDMA over WDM passive optical network (PON) as a solution for the gigabit-symmetric FTTH systems will be proposed. The system architecture and the WDM interchannel crosstalk will be studied. It will be shown that by taking advantage of reflection spectrum notches of the SSFBG en/decoder, the WDM interchannel crosstalk can be suppressed and can enable OCDMA over WDM PON to simultaneously provide multigigabit-per-second up- and downlinks to a large number of users.