As the demand for broadband applications continues rising, low cost and high capacity PON system has attracted more attention to keep up with the increasing demand in the future access network. Recently, the IEEE 802.3 Ethernet Working Group has already sponsored the discussion of next generation Ethernet passive optical network (NG-EPON) to provide 25-Gb/s per wavelength. In order to upgrade current 10-Gb/s PON to realize the capacity of 100 Gb/s PON with 25 Gb/s per wavelength, a variety of experimental demonstrations have shown the feasibility of 25-Gb/s per wavelength using the modulation schemes of four-level pulse amplitude modulation (PAM-4), electrical duobinary (EDB), optical duobinary (ODB) or non-return-to-zero on-off-keying (NRZ-OOK) for high speed transmission. In order to achieve higher performance, these transmission schemes are always combined with the advanced digital signal processing (DSP) which increases the technical complexity and the cost as well. Most of the previous demonstration are based on the off-line processing, therefore requires more time for the practical deployment.
In this paper, we demonstrate the first field trial a real-time 100Gb/s TWDM-PON system with 4×25-Gb/s downstream and 4×10-Gb/s upstream transmission using 10G-class directly-modulated lasers (DMLs) and APD/PIN receivers. A single delay-interferometer (DI) is used to achieve frequency equalization as well as chirp management to increase the high frequency components of the system response and combat the chromatic dispersion (CD) during the fiber transmission. Note that there is no DSP applied for the whole system. Electrical clock/data recovery (CDR) chips are integrated on the main board for data generation, recovery and real-time bit error rate (BER) measurement. We obtained a power budget of 33 dB with 0-40km of standard single mode fiber based on NRZ-OOK modulation format for the downstream. The system stability is also verified using deployed 40-km fiber infrastructure over 67-hour real-time measurement.