10- and 40-Gb/s forward error correction devices for optical communications

Two standard forward error correction (FEC) devices for 10- and 40-Gb/s optical systems are presented. The first FEC device includes RS(255, 239) FEC, BCH(4359, 4320) FEC, and standard compliant framing and performance monitoring functions. It can support a single 10-Gb/s channel or four asynchronous 2.5-Gb/s channels. The second FEC device implements RS(255, 239) FEC at a data rate of 40 Gb/s. This paper presents the key ideas applied to the design of Reed-Solomon (RS) decoder blocks in these devices, especially those for achieving high throughput and reducing complexity and power. Implemented in a 1.5-V, 0.16-μm CMOS technology, the RS decoder in the 10-Gb/s, quad 2.5-Gb/s device has a core gate count of 424 K and consumes 343 mW; the 40-Gb/s RS decoder has a core gate count of 364 K and an estimated power consumption of 360 mW. The 40-Gb/s RS FEC is the highest throughput implementation reported to date.