Greta Light

A duplex 10 Gb/s serial active optical cable for short-reach applications

Optical links offer many advantages over copper based solutions for 10 Gb/s interconnects, including lighter weight, longer reach and lower power consumption. Copper solutions are either very bulky and of limited reach (10GBASE-CX4) or have high power dissipation (>10W for a 10GBASE-T link). Previous optical solutions for high-volume, short interconnects have been limited by cost and connector cleanliness considerations. In this paper, we describe a duplex active optical cable which overcomes these limitations. Active optical cables not only retain the advantages of optical links with the external characteristics of an electrical cable, but provide additional advantages in performance and yield by eliminating the extra link margins inherent in open optical link standards. A new electrical connector is described which provides excellent return loss performance, high density and a rugged, consumer friendly design. Performance results for 15m graded index plastic optical fiber and 100m multimode glass fiber based cables are reported. Low jitter contribution and power dissipation of ~1W per link are achieved. Finally the design and performance of adapters allowing the use of this cable in present SFP+ and XFP transceiver systems is presented.