Abstract

There has been much progress in high-capacity optical networks using wavelength division multiaccess (WDMA) with tunable Fabry–Perot receiver filters.¹ To improve the channel capacity as limited by the filter cross talk,² we propose a two-layer network combining microwave subcarrier multiplexing (SCM) with wavelength division multiplexing (WDM) to link to potentially ≃ 1,000 channels with full connectivity. Among the advantages of this two-layer approach are flexibility in service upgrade, relaxed tolerances on the optical filter, potentially low-cost components, and possible protocol simplification. We have demonstrated experimentally a two-channel, frequency-shift-keyed (FSK) subcarrier optical link at 200 MB/s, the highest multiple-subcarrier FSK modulation speed reported to our knowledge.^3,4 Calculations indicate that 640 channels can be realized with optical filters, optical fiber amplifiers, and rf components.

© 1991 Optical Society of America