Design and demonstration of a colorless WDM-OFDMA PON system architecture achieving symmetric 20-Gb/s transmissions with residual interference compensation

Abstract

In this paper, we propose a two-tiered colorless WDM-OFDMA PON system architecture that draws strengths from each individual WDM and OFDM PON systems. Specifically, the two-tiered architecture enables a colorless transceiver to be shared by a group of ONUs, resulting in drastic reduction of the system cost. For achieving colorlessness via reusing downstream light sources, we discover the residual power of downstream signal unexpectedly springs back after transmissions, causing severe interference to the upstream signal, and thus limiting the data rate of the upstream signal. We devise a method of adopting a common dispersion compensation module at OLT to reduce the residual power over all wavelengths. Experimental results show that, with an improvement of upstream signal's SNR up to 10 dB, the system successfully achieves 20-Gb/s bidirectional OFDM-signal transmissions on the same wavelength over a 20-km SMF.

Bidirectional WDM-OOFDM access network based on a sliceable optical transceiver with colorless ONUs

“…End-to-end real time colorless transmissions of IMDD OOFDM signals were also reported by using reflective semiconductor optical amplifiers (RSOA) intensity modulators [10], and furtherly improved REAM-IM-based system allowed to demonstrate bidirectional, real-time, colorless 10Gb/s over 25 km SSMFs [11]. Other approaches employ RSOAs [12][13] or gain saturated SOAs [14] in the ONU. Moreover, multicarrier sources based on external cavities [15], semiconductor mode-locked [16] or distributed feedback [17] lasers have demonstrated 10 Gb/s over 50 km and beyond by using DD-OFDM systems.…”

Single-Fiber Lightwave Centralized WDM-OFDMA-PON With Colorless Optical Network Units

“…Thus, WDM-OFDMA-PON, combining the key advantages of the two strategies, is emerging as a promising solution [5]. All architectures demonstrated in [6]- [14] exploit direct-detection optical OFDM (DDO-OFDM) for downlink (DL) to minimize signal reception cost at ONU. In [6]- [10], the uplink (UL) is also directly detected at optical line terminal (OLT) receivers.…”

“…All architectures demonstrated in [6]- [14] exploit direct-detection optical OFDM (DDO-OFDM) for downlink (DL) to minimize signal reception cost at ONU. In [6]- [10], the uplink (UL) is also directly detected at optical line terminal (OLT) receivers. This architecture allows a simple transceiver for both ONU and OLT, but leads to poor performance for the UL signal.…”