Distributed Raman amplification using ultra-long fiber laser with a ring cavity: characteristics and sensing...

Area of Science:

• Optical Engineering
• Telecommunications
• Sensing Technology

Background:

• Distributed Raman amplification (DRA) is crucial for long-haul optical communication and sensing.
• Ultra-long fiber laser (UL-FL) pumping with a ring cavity offers potential for enhanced DRA performance.
• Optimizing pumping schemes is key to overcoming limitations like nonlinear impairments and noise.

Purpose of the Study:

• To investigate the characteristics of ring-cavity based DRA using UL-FL pumping.
• To compare forward and backward pumping configurations for gain, nonlinear impairment, and noise figure.
• To demonstrate an ultra-long-distance distributed sensing application.

Main Methods:

• Full investigation of gain, nonlinear impairment, and noise figure for forward and backward pumping.
• Implementation of a ring-cavity based DRA scheme with UL-FL.
• Demonstration of Brillouin optical time-domain analysis (BOTDA) over 142.2 km fiber.

Main Results:

• Achieved ultra-long-distance distributed sensing over 142.2 km without repeaters.
• Demonstrated 5m spatial resolution and ± 1.5 °C temperature uncertainty in BOTDA.
• Attributed performance improvement to uniform gain distribution and suppressed pump-probe relative intensity noise (RIN) transfer.

Conclusions:

• The proposed ring-cavity based DRA scheme with UL-FL pumping is highly effective for repeaterless applications.
• Optimized system design provides uniform gain and significantly reduces RIN transfer, enhancing performance.
• The system enables high-performance ultra-long-distance distributed sensing.