Synchronous CDMA technique for fiber-optic LANs with folded dual bus topology

The synchronization in the code-division multiple-access (CDMA) fiber-optic networks reduces interchannel interference, permits larger number of stations, and gives higher throughput. In the star topology proposed, very strict synchronization of transmitters and equalization of propagation delays over various paths in the network is achieved since a single optical source is used for the whole network, and all the signals follow that same path around the network. Other advantages are that the operation mode of the optical source is pulsed, not continuous-wave, and the attenuation variations among interfering signals are low. The major disadvantage of the proposed system is in its stricter power constraints. This problem can be alleviated by the insertion of optical amplifiers when the number of stations outgrows the limits of the basic network