Cost-effective adaptive optical network technologies for Metropolitan Area Networks

High-performance FPGA implementations of volterra DFEs for optical fiber systems

“…On the contrary, in the cases of VDFE(5, 3) and VDFE (7,4), the reduction of the frequency is proportional to the increase of parallelism, so the throughput remains the same. Furthermore, the elimination of some of the multipliers providing the inputs and adders summing the outputs of the FIR filters of the Volterra kernel leaves more DSP resources to be utilized by cascaded FIR filters.…”

“…Thus, communication systems based on the Intensity Modulation/Direct Detection (IM/DD) scheme, where the optical to electrical conversion is done via a photo-detector (acts as a square-law function), have been used extensively for 10 Gb/s up to 40 Gb/s optical links [1], [2]. Although coherent optical systems have been recently introduced achieving higher transmission rates, direct detection provides the luxury of low-cost and simple receiver modules amenable for metropolitan networks [4].…”

“…Channel equalizers are used at the receiver part to suppress the Intersymbol Interference (ISI), which is the result of the overlapping between the current symbol with previous and subsequent ones [4]- [10]. To achieve this, Decision Feedback Equalizers (DFEs) are widely used [11].…”

“…Thus, DFEs based on recursive Volterra filters (Volterra DFEs -VDFEs) have been proposed [4], [5], [8]- [10]. Compared to conventional DFEs, the VDFEs achieve better quality as they handle more efficiently the non-linearities of the optical receiver and they can be used in long-distance communication links.…”