Practical and cost-effective high-fidelity optical carrier dissemination using coherent communication techniques.

Area of Science:

• Optical Communications
• Telecommunications Engineering
• Laser Physics

Background:

• High-fidelity optical carrier dissemination is crucial for advanced telecommunication networks.
• Existing methods face challenges in long-haul transmission and signal recovery over deployed fiber infrastructure.

Purpose of the Study:

• To present a novel unidirectional frequency dissemination scheme for high-fidelity optical carriers.
• To demonstrate the feasibility of transmitting and recovering optical signals over a significant distance in a real-world telecommunication network.

Main Methods:

• Transmission of a 10 Gb/s Binary Phase Shift Keying (BPSK) signal from an ultra-narrow linewidth laser.
• Utilized a 124 km field-installed optical fiber link without inline optical amplification.
• Employed coherent communication techniques and optical injection-locking for carrier recovery and noise suppression.

Main Results:

• Successfully transmitted and recovered an optical carrier signal over 124 km of deployed fiber.
• Achieved carrier recovery with significant noise suppression.
• Measured a beat signal linewidth of 2.8 kHz between the original and recovered carriers.
• Demonstrated fractional frequency instabilities of 3.3 × 10(-14) at 1 s averaging time before phase noise cancellation.

Conclusions:

• The proposed unidirectional frequency dissemination scheme enables high-fidelity optical carrier transmission over telecommunication networks.
• The technique is effective even without inline optical amplification, showcasing robustness.
• The achieved signal quality and stability are suitable for next-generation optical communication systems.