MDM-TDM PON Utilizing Self-Coherent Detection-Based OLT and RSOA-Based ONU for High Power Budget

A cost-effective mode-division-multiplexing and time-division-multiplexing passive optical network (MDM-TDM PON) utilizing a self-coherent detection for upstream signal at optical line terminal (OLT) and a high-gain reflective semiconductor optical amplifier (RSOA) as an optical amplifier for a downstream signal at optical network units (ONUs) to enhance bidirectional power budget is proposed. Meanwhile, to further reduce the cost of ONU, RSOA is also used as upstream on-off keying (OOK) signal modulator by time compression multiplexing. A novel dual-modulus algorithm is proposed for OOK signal detection at the OLT. We experimentally verify the proposed MDM-TDM PON architecture with an upstream 1-Gb/s OOK signal and a downstream 10-Gb/s orthogonal frequency division multiplexing (OFDM) signal. Due to the high gain of RSOA and high receiver sensitivity of self-coherent detection, a 30-dB bidirectional power budget is achieved after 10-km few-mode fiber and a 20-km standard single-mode fiber at the bit error rate (BER) of 10
^-3
. Optimal seed power and signal power that input to the RSOA are investigated in this paper.