Advances in Spectral Optical Code-Division Multiple-Access Communications

Code-division multiple-access (CDMA) has flourished as a successful wireless networking technology in mobile cellular telephony, and wireless local area networks (LAN) such as the unlicensed industry, science, and medicine (ISM) bands. The commercial exploitation of the benefits of CDMA raises the question as to whether optical code-based communications offer significant benefits to an optical network and what are the technologies that enable code-based optical networks. Recent investigations of optical CDMA (OCDMA) strategies have addressed this question through numerous laboratory-based test-bed studies of multiuser link and recent experimental field trials conducted on in-the-ground fiber. OCDMA requires its own physical layer technologies that are distinctly different from widely pursued wavelength-division-multiplexed (WDM) all-optical networks. Simulations of multiuser performance predict ultimate link capacity and the performance of broadcast and select synchronous nets with strong central management as well as asynchronous architectures with reduced centralized management.