Efficient and reliable digital sub-band multiplexed nonlinear frequency division multiplexing system

Area of Science:

• Optical Communications
• Signal Processing

Background:

• Nonlinear Frequency Division Multiplexing (NFDM) offers an advantage by mitigating fiber nonlinear effects.
• However, NFDM systems face limitations in spectral efficiency due to guard intervals (GI) required for chromatic dispersion (CD) compensation.

Purpose of the Study:

• To introduce a novel Digital Sub-band Multiplexed (DSBM) NFDM system to enhance spectral efficiency.
• To investigate the suitability of different subcarrier shaping techniques within the DSBM-NFDM framework.

Main Methods:

• Development and numerical simulation of a DSBM-NFDM system.
• Comparison of root raised cosine (RRC) shaped subcarriers against orthogonal frequency division multiplexing (OFDM) shaped subcarriers.
• Evaluation of system performance in terms of effective information rate (EIR) and net information rate.

Main Results:

• The proposed DSBM-NFDM system significantly reduces the minimal required guard interval.
• Root raised cosine (RRC) shaped subcarriers demonstrated superior performance compared to OFDM in the DSBM-NFDM system.
• A 129.7% improvement in effective information rate (EIR) was achieved compared to single channel (SC) NFDM.
• A net information rate of 531.0 Gbps over 960 km with a spectral efficiency (SE) of 3.86 bit/s/Hz was demonstrated, below the HD-FEC threshold.

Conclusions:

• The DSBM technique is effectively introduced into NFDM systems for the first time.
• The DSBM-NFDM system offers a substantial increase in information rate and spectral efficiency.
• This work presents a novel subcarrier shaping scheme for NFDM with potential for practical implementation.