Sharing of the optical band in local systems

Ways of supporting large numbers (on the order of thousands) of simultaneous high-speed ( approximately 10 Mb/s) users on the lowest hierarchical unit of a coherent optical system are investigated. Assuming each channel uses a different optical carrier, a key impairment is laser phase noise, which causes modulated optical carriers, nominally widely separated in frequency, to not be truly spectrally disjoint. To deal with this problem in consideration of the superabundance of optical bandwidth, attention is focused on the region of low spectral utilization. For this region, formulas are derived that describe the performance of three arrangements of optical channels: equally spaced carriers, randomly placed carriers, and randomly placed carriers with spread spectrum. The formulas quantify the great superiority of equally spaced carriers over random placement, despite the highly significant benefit afforded by spread spectrum. Numerical examples are worked out to show this result. >

[1]  G. Jacobsen,et al.  Theory for heterodyne optical ASK receivers using square-law detection and postdetection filtering , 1987 .

[2]  Adel A. M. Saleh,et al.  Reflective single-mode fiber-optic passive star couplers , 1988 .

[3]  G. Hill,et al.  The application of coherent optical techniques to wide-band networks , 1987 .

[4]  Frank W. J. Olver,et al.  Introduction to Asymptotics and Special Functions , 1974 .

[5]  A. Chraplyvy,et al.  Narrowband tunable optical filter for channel selection in densely packed WDM systems , 1987 .

[6]  Ralf-Peter Braun,et al.  System limitations due to four-wave mixing in single-mode optical fibres , 1986 .

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

[8]  J. Salz,et al.  Modulation and detection for coherent lightwave communications , 1986, IEEE Communications Magazine.

[9]  B. Kasper,et al.  Densely spaced WDM coherent optical star network , 1987 .

[10]  Larry J. Greenstein,et al.  Noncoherent detection of coherent lightwave signals corrupted by phase noise , 1988, IEEE Trans. Commun..

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

[12]  L. Kazovsky,et al.  ASK multiport optical homodyne receivers , 1987 .

[13]  Jack Salz.  Coherent lightwave communications , 1985, AT&T Tech. J..

[14]  P. Healey.  Effect of intermodulation in multichannel optical heterodyne systems , 1985 .

[15]  Govind P. Agrawal.  Evaluation of crosstalk penalty in multichannel ASK heterodyne optical communication systems , 1987 .

[16]  L. Kazovsky.  Multichannel coherent optical communications systems , 1987 .

[17]  Athanasios Papoulis,et al.  Probability, Random Variables and Stochastic Processes , 1965 .

[18]  Leonid G. Kazovsky,et al.  Performance analysis and laser linewidth requirements for optical PSK heterodyne communications systems , 1986 .

[19]  G. Jacobsen,et al.  The effect of laser linewidth on coherent optical receivers with nonsynchronous demodulation , 1987 .