Three-dimensional constellation diagram with a hierarchical level design for multi-core transmission

Area of Science:

• Optical communication
• Signal processing
• Information theory

Background:

• Traditional constellation diagrams in optical communication systems face limitations in optimizing signal transmission efficiency.
• Geometric shaping (GS) offers a potential method for improving constellation performance by manipulating spatial coordinates.
• Reducing bit error rate (BER) is crucial for reliable data transmission in high-speed communication networks.

Purpose of the Study:

• To propose and verify a novel three-dimensional constellation diagram for optimizing spatial coordinates.
• To enhance the constellation figure of merit (CFM) and consequently reduce the bit error rate (BER).
• To demonstrate the practical application and performance gains in a fiber optic communication system.

Main Methods:

• Development of a novel three-dimensional constellation diagram utilizing geometric shaping (GS).
• Implementation of a three-dimensional carrier-free amplitude phase (CAP) modulated signal transmission at 25.45Gb/s.
• Experimental verification on a seven-core fiber communication system.

Main Results:

• The proposed constellation diagram achieved an average receiver sensitivity gain of 1.4dB at a BER of approximately 1×10⁻³.
• A receiver sensitivity gain difference of 1.3dB was observed between different fiber cores.
• The method effectively reduces BER without requiring additional communication components.

Conclusions:

• The novel 3D constellation diagram with GS is effective in improving receiver sensitivity and reducing BER in optical communication.
• The proposed scheme offers practical advantages for short-distance access networks due to its efficiency and lack of additional hardware.
• This advancement contributes to more reliable and efficient optical data transmission.