Coherent optical communication: towards realtime systems at 40 Gbit/s and beyond

Area of Science:

• Optical Communications
• Digital Signal Processing
• Telecommunications Engineering

Background:

• Coherent optical communication systems offer enhanced performance but face real-time implementation challenges.
• Offline experiments have demonstrated the significant potential of these advanced transmission systems.
• Key technological components are crucial for enabling real-time coherent optical communication.

Purpose of the Study:

• To review recent advancements in real-time coherent communication technologies.
• To present the design and performance of a real-time Quadrature Phase-Shift Keying (QPSK) transmission system.
• To evaluate the system's Bit Error Rate (BER) against the Forward Error Correction (FEC) threshold.

Main Methods:

• Implementation of a real-time coherent optical transmission system.
• Integration of a 3x3 coupler within the receiver architecture.
• Testing the system at a data rate of 1.4 Gbit/s.

Main Results:

• Successful real-time operation of a coherent QPSK transmission system.
• Achieved a Bit Error Rate (BER) significantly below the FEC threshold.
• Demonstrated the viability of the implemented receiver components for high-speed communication.

Conclusions:

• The developed real-time coherent QPSK system meets the stringent requirements for advanced optical networks.
• The use of a 3x3 coupler in the receiver is effective for achieving low BER.
• This work paves the way for practical, high-performance real-time coherent optical communication systems.