Power Budget Improved Symmetric 40-Gb/s Long Reach Stacked WDM-OFDM-PON System Based on Single Tunable Optical Filter

We propose a stacked wavelength-division-multiplexed orthogonal-frequency-division-multiplexed passive optical network (WDM-OFDM-PON) system that is capable of transmitting 10-Gb/s per wavelength downstream OFDM signals and directly modulated upstream on-off keying (OOK) signals up to 100 km without any repeater. In this scheme, we use our specially designed electronic controlled liquid tunable optical filter to simultaneously select downstream signals and process upstream signal chirp. By experiment, we demonstrate this bidirectional transmission system and achieve error-free transmission performance over different fiber distances. A power budget of 35.6 dB for 25-km fiber transmission is obtained to support 1 : 512 splitting ratios. Through 100-km fiber transmission, a 34.4-dB optical power budget with a nonrepeater is also achieved. Moreover, the effects of various system parameters such as filter profile and downstream signals' launched power, are also investigated in detail by simulation and experiment for improving system performance.