Ultrafast All-Optical Code-Division Multiple-Access (CDMA) Fiber-Optic Networks

Abstract With the advanced development of fiber-optics, the large bandwidth-expansion required by spread spectrum code-division multiple-access (CDMA) can now be accomodated by using a fiber-optic channel for transmission and incoherent optical signal processing for code generation and correlation. Optical synchronous CDMA (S/CDMA), a synchronous transmission format, is introduced and compared with optical (asynchronous) CDMA. Using modified prime sequence codes, S/CDMA is shown to accomodate a larger number of subscribers and more simultaneous users than CDMA. A two-user experiment demonstrating the feasibility of optical S/CDMA is performed at 10 Mbit/s (500 Mchip/s), using optical signal processing. (A chip is a bit-representation component; please see Section 2.) An environment in which S/CDMA would be particularly suited is also discussed. In addition, recent research shows that the feasibility of optical CDMA is also determined by the architecture of the optical encoders/decoders. The coding architecture affects, for example, the amount of power loss and length of optical delays associated with code sequence generation and correlation, which, in turn, affect the power budget, size, and cost of an optical CDMA system. Therefore, a new, modified 2 n coding architecture is proposed and compared with prime and 2 n coding architectures. Study shows that the modified 2 n architecture performs the best and is particularly suitable for ultrafast all-optical processing and waveguides implementation for the future all-optical CDMA networks. A 100 Mbit/s optical CDMA experiment in free space demonstrating the feasibility of the modified 2 n coding architecture, using a serial combination of 50/50 beam splitters and retroreflectors, at 10 Tchip/s (i.e., 100,000 chip/bit) with 100 fs laser pulses is also reported.

[1]  J.A. Salehi.  Emerging optical code-division multiple access communication systems , 1989, IEEE Network.

[2]  L. Kleinrock,et al.  Packet Switching in Radio Channels: Part I - Carrier Sense Multiple-Access Modes and Their Throughput-Delay Characteristics , 1975, IEEE Transactions on Communications.

[3]  R. W. Nettleton,et al.  A spread-spectrum technique for high-capacity mobile communications , 1977, IEEE Transactions on Vehicular Technology.

[4]  F. E. Ross,et al.  Rings are 'round for good! , 1987, IEEE Network.

[5]  Michel E. Marhic,et al.  Pulse coding and coherent decoding in fibre-optic ladder networks , 1989 .

[6]  Paul R. Prucnal,et al.  Spread spectrum fiber-optic local area network using optical processing , 1986 .

[7]  David A. Jackson,et al.  Spread-spectrum optical fibre network based on pulsed coherent correlation , 1990 .

[8]  Joseph Y. N. Hui,et al.  Throughput analysis for code division multiple accessing of the spread spectrum channel , 1984, IEEE Transactions on Vehicular Technology.

[9]  R. Blahut.  Theory and practice of error control codes , 1983 .

[10]  R. Petrovic,et al.  Orthogonal codes for CDMA optical fibre LANs with variable bit interval , 1990 .

[11]  Paul R. Prucnal,et al.  Ultrafast All-Optical Synchronous Multiple Access Fiber Networks , 1986, IEEE J. Sel. Areas Commun..

[12]  W H Knox,et al.  How fast is excitonic electroabsorption? , 1990, Optics letters.

[13]  George R. Cooper,et al.  A spread-spectrum technique for high-capacity mobile communications , 1978 .

[14]  Michel E. Marhic,et al.  2/sup n/ codes for optical CDMA and associated networks , 1990, LEOS Summer Topical on Optical Multiple Access Networks.

[15]  Wing C. Kwong,et al.  Programmable ultrafast all-optical code-division multiple access networks , 1992 .

[16]  Thomas G. Robertazzi,et al.  Critical connectivity phenomena in multihop radio models , 1989, IEEE Trans. Commun..

[17]  Joseph Y. Hui.  Pattern Code Modulation and Optical Decoding - A Novel Code-Division Multiplexing Technique for Multifiber Networks , 1985, IEEE Journal on Selected Areas in Communications.

[18]  David A. Jackson,et al.  Coherent optical fiber communications system using all-optical correlation processing. , 1990, Optics letters.

[19]  L. B. Milstein,et al.  Theory of Spread-Spectrum Communications - A Tutorial , 1982, IEEE Transactions on Communications.

[20]  A. A. Shaar,et al.  Prime sequences: quasi-optimal sequences for OR channel code division multiplexing , 1983 .

[21]  Y M Liu,et al.  Simple method to start and maintain self-mode-locking of a Ti:sapphire laser. , 1992, Optics letters.

[22]  Robert C. Dixon,et al.  Spread‐spectrum systems , 1976 .

[23]  A. Holmes,et al.  All-optical CDMA using 'quasi-prime' codes , 1992 .

[24]  Wing C. Kwong,et al.  Performance comparison of asynchronous and synchronous code-division multiple-access techniques for fiber-optic local area networks , 1991, IEEE Trans. Commun..

[25]  J. Goodman,et al.  Fiber-optic lattice signal processing , 1984, Proceedings of the IEEE.

[26]  G. Vannucci.  Combining frequency-division and code-division multiplexing in a high-capacity optical network , 1989, IEEE Network.

[27]  M.A. Santoro,et al.  Asynchronous fiber optic local area network using CDMA and optical correlation , 1987, Proceedings of the IEEE.

[28]  S. Tamura,et al.  Optical code-multiplex transmission by gold sequences , 1985 .

[29]  Paul R. Prucnal,et al.  'Synchronous' CDMA demonstration for fibre-optic networks with optical processing , 1990 .

[30]  R I Macdonald.  Fully orthogonal optical-code multiplex for broadcasting. , 1988, Optics letters.

[31]  Jawad A. Salehi,et al.  Code division multiple-access techniques in optical fiber networks. I. Fundamental principles , 1989, IEEE Trans. Commun..

[32]  Gerard J. Foschini,et al.  Using spread-spectrum in a high-capacity fiber-optic local network , 1988 .

[33]  Paul R. Prucnal,et al.  Wavelength‐division integration of services in fibre‐optic networks , 1988 .

[34]  J. Goodman,et al.  Optical fiber delay line signal processing , 1984 .

[35]  Giovanni Vannucci,et al.  Experimental spreading and despreading of the optical spectrum , 1989, IEEE Trans. Commun..

[36]  H. Kochevar,et al.  Spread Spectrum Multiple Access Communications Experiment Through a Satellite , 1977, IEEE Trans. Commun..

[37]  Jawad A. Salehi,et al.  Code division multiple-access techniques in optical fiber networks. II. Systems performance analysis , 1989, IEEE Trans. Commun..

[38]  Fan Chung Graham,et al.  Optical orthogonal codes: Design, analysis, and applications , 1989, IEEE Trans. Inf. Theory.

[39]  P. Vijay Kumar,et al.  Optical orthogonal codes-New bounds and an optimal construction , 1990, IEEE Trans. Inf. Theory.