The passive optical fiber bus LAN based on four port full bi-directional couplers

A three port asymmetrical bi-directional optical coupler (ABC) is proposed. A novel method of modeling a four port full bi-directional coupler using the ABC couplers is presented and a comparison of the signal loss due to the novel four port bi-directional coupler and the four port optical coupler made with the traditional three port optical couplers is given. A computer model comparison of bus local area networks using these two types of four port optical couplers demonstrates that the new bus has the potential to support an increase of two to five times the number of nodes. The performance results for the bus networks using the novel four port full bi-directional couplers, four port couplers consisting of a combination of traditional three port couplers of 10:90 and 50:50 coupling ratios, and four port couplers consisting of all 50:50 traditional three port couplers are given