Performance evaluation of multilevel modulation formats using partial response for capacity upgrade in access network with limited electronic bandwidth

• Evaluation of NRZ, duobinary, 4-PAM and duobinary 4-PAM based on BER performance.
• Proposed duobinary modulation can decrease bandwidth from 9 GHz to 4 GHz.
• Proposed 4-PAM modulation enables transmission of 18 Gbps over 20 km of fiber.
• Proposed combination of duobinary and 4-PAM modulation performs below FEC limit.

We present a successful experimental evaluation of 4 level Pulse Amplitude Modulation (4-PAM) and Duobinary modulation. An experimental performance evaluation is presented for Duobinary 4 PAM and other modulation formats. All modulation formants used, may be considered to be implemented in future Passive Optical Network (PON) class access networks with limited electrical bandwidth. We compared NRZ, Duobinary, 4-PAM and Duobinary 4-PAM operating at 9 Gbaud over 20 km single mode fiber. The results provides an insight and guidelines on the utilization of these advanced modulation formats.