Cost-effective coherent PON using silicon Mach-Zehnder modulator and digital carrier regeneration

We propose a cost-effective coherent passive optical network (PON) by employing the linear silicon Mach-Zehnder modulator (MZM) with computationally-efficient digital signal processing (DSP). The proposed PON adopts the intensity modulation and coherent detection scheme with discrete multi-tone (DMT) signal to achieve both high spectral efficiency (SE) and receiver sensitivity. Meanwhile, a digital carrier regeneration (DCR) method is proposed to further reduce the optical carrier-to-signal power ratio of intensity modulated DMT signal based on silicon MZM, which will significantly increase the achievable system power budget, especially when a high-order modulation format is adopted. No carrier frequency offset and phase estimations are needed in the receiver, which greatly reduces the complexity for both laser and DSP in coherent detection. Finally, a 10-Gb/s/ch uplink transmission is experimentally demonstrated using the proposed DCR method over 20-km standard single-mode fiber (SSMF), achieving about -44dBm sensitivity under the 7% forward-error-correction (FEC) limit of bit error ratio (BER) = 3.8x10(-3).