Simple intradyne PSK system for udWDM-PON.

Area of Science:

• Optical Communications
• Photonics
• Telecommunications Engineering

Background:

• Ultra-dense wavelength-division multiplexing passive optical networks (WDM-PON) require advanced receiver technologies.
• Traditional coherent receivers often rely on complex and expensive components like 90° hybrids.

Purpose of the Study:

• To present a novel homodyne coherent receiver for WDM-PON utilizing off-the-shelf components.
• To optimize the receiver for Binary Phase Shift Keying (BPSK) signals and evaluate its performance.

Main Methods:

• The receiver employs a conventional Distributed Feedback (DFB) laser, a phase-switched clock signal, an optical coupler (replacing a 90° hybrid), balanced photodetectors, and digital signal processing.
• Phase swing optimization for DBPSK signals was performed.
• Experimental evaluation of receiver sensitivity against varying laser linewidths, frequency offset, and clock time delay.

Main Results:

• Achieved a receiver sensitivity of -48 dBm at a Bit Error Rate (BER) of 10⁻³.
• Demonstrated high tolerance to phase noise, a critical factor in coherent detection.
• Assessed acceptable frequency offset and clock time delay limits for system operation.

Conclusions:

• The proposed homodyne coherent receiver offers a cost-effective and high-performance solution for ultra-dense WDM-PON.
• The use of off-the-shelf components and an optical coupler simplifies the design without compromising sensitivity.
• The receiver's robustness to phase noise and timing impairments makes it suitable for practical deployment.