Polarization in Retracing Circuits for WDM-PON

Abstract

Reflective semiconductor optical amplifier (RSOA)-based network-embedded self-tuning solutions for colorless optical network unit in wavelength-division-multiplexed passive optical network architecture suffer the device polarization-dependent gain (PDG). The Faraday-mirror-based topology proposed in the literature for low PDG RSOA is not suitable for high PDG RSOA. A polarization retracing circuit is proposed and discussed to comply with the high PDG RSOA. The polarization evolution is theoretically and experimentally analyzed in the presence of a high PDG RSOA comparing three cases: standard topology with standard mirror, the retracing circuit proposed in the literature with a Faraday rotator mirror (FRM), and the proposed retracing circuit, which includes both an FRM and a Faraday rotato

Efficient modulation cancellation usingreflective SOAs

“…1(b), is the self-seeded configuration [2,3]. In this case, a laser cavity is formed between the ONU RSOA and the Faraday rotating mirror (FRM) at the remote node [4]. The FRM is necessary to unwind the polarization rotation experienced by the laser field over a complete round-trip of the long cavity.…”

Bit- and Power-Loading—A Comparative Study on Maximizing the Capacity of RSOA Based Colorless DMT Transmitters

“…The FRM and the RSOA reflective facet form the Fabry-Perot resonator cavity embedded in the DF. In case of RSOA with high polarization dependent gain (HPDG), the FR and FRM cancel out the birefringence effect in the cavity and maintain a constant polarization at the RSOA input [42]. The coupler at the RN has a coupling ratio of 90/10, where 90% of the power is kept in the cavity and 10% is transmitted to the CO.…”

Self-Seeded RSOA-Fiber Cavity Lasers vs. ASE Spectrum-Sliced or Externally Seeded Transmitters—A Comparative Study

“…The FRM and FR are needed, since RSOAs often have a polarization-dependent gain (PDG). With this arrangement the forward and backward propagating signals maintain the polarization state at the RSOA [35]. A 90/10 power splitter sends 10% of the power through the feeder fiber (FF) to the CO. At the CO, the signal is pre-amplified and directly detected with a photodiode.…”

“…An optical bandpass filter (OBPF) mimics the WGR WDM filter at the remote node (RN). In (b), a Faraday rotator (FR) and FR-mirror (FRM) are placed at the ONU and the RN, respectively, for polarization control in the RSOA-FCL [35], shown by the yellow shading. The ONU is connected to the RN and the CO through the distribution fiber (DF) and the feeder fiber (FF), respectively.…”