Improved self-seeding and carrier remodulation performance for WDM-PON by means of double RSOA erasure

In this work, we investigated a novel wavelength division multiplexing passive optical network (WDM-PON) configuration, based on cascaded reflective semiconductor optical amplifiers (RSOA) data erasure for combined self-seeding and wavelength reuse. Improved performance is achieved by enhanced erasure efficiency using a self-seeded double-RSOA cavity at the optical line terminal (OLT) and cascaded RSOAs at the optical network terminal (ONT). To carry out the study, our experimental results for our earlier combined topology layout operating at a symmetric transmission were used to validate the simulation framework for the proposed double-RSOA erasure configuration. Using our original single-cavity self-seeding WDM-PON architecture as a benchmark, downstream extinction ratio (ERD) margins of 6.5 dB and 9.0 dB are obtained, for generating self-seeded downstream signals and upstream remodulation, respectively. Also, bidirectional transmission of 1.25 Gb/s over links reach up to 45 km is achieved by the double-RSOA cavity, surpassing in 25 km our original combined topology. The results indicated that our proposition effectively addresses a fundamental trade-off for WDM-PONs based on the wavelength reuse and/or self-seeding techniques. Specifically, the double erasure procedure allows the use of relatively high levels of ERD, thereby providing improved bit error rate (BER) at the ONT, while assuring high-quality generation of the self-seeding carrier and loopback operation.