Power-Efficient Layout of a Fiber-Optic Multistar that Permits Log2 N Concurrent Baseband Transmissions Among N Stations

A passive, single-hop, fiber-optic interconnection among N stations, each with two transmitters and one receiver, and a round-robin transmission schedule for it, which jointly permit log2 N concurrent noninterfering transmissions on a single wavelength, has recently been described. This is a substantial improvement over the previously known limit of two concurrent transmissions, but the layout of this interconnection poses a challenge both in terms of wiring complexity and path loss. In this paper, a power-efficient implementation of this interconnection using several stages of balanced fiber-optic star couplers is presented. With lossless components, path loss is N. the same as a single-star interconnection that permits only a single transmission at a time. Consequently, the high degree of parallelism translates into higher capacity. The required number of (2 × 2) star couplers is also very similar to that required for implementing a single N × N) star.