Optical Repeater Reverse Pump Light System
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Solution Overview
Problem
Submarine cable optical repeaters using erbium doped fiber amplifiers face issues with signal-to-noise ratio degradation due to spontaneous emission noise accumulation and pump failures, leading to service interruptions and low reliability, especially with high-speed signal transmission and failure of multiple pumps.
Innovation Solution
The optical repeater design incorporates a reverse pump light system that couples residual Raman pump lights from end stations to erbium doped fibers, ensuring continued signal amplification even when local pump lights fail, thereby maintaining system reliability and preventing severe OSNR degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If erbium doped fiber amplifier is used to simplify design and improve reliability, then design complexity is reduced and system reliability is improved, but optical signal-to-noise ratio degrades due to spontaneous emission noise accumulation
Solution Approach 1:
A Raman amplifier is introduced as an intermediary component before the EDFA. The Raman amplifier uses stimulated Raman scattering to provide pre-amplification with lower noise characteristics, thereby reducing the noise figure of the overall amplifier system while maintaining the reliability benefits of the EDFA
2Reliability
If multiple pumps are used for redundancy backup to maintain high output power, then output power is maintained and OSNR degradation is prevented, but device complexity and power consumption increase
Solution Approach 1:
The Raman amplifier is configured to operate in advance before the EDFA. By providing pre-amplification with multiple Raman pumps, the system ensures that even if the EDFA or its pumps fail, the Raman amplifier can maintain sufficient output power and OSNR, thereby providing redundancy without requiring duplicate EDFA pump configurations
3Productivity
If signal transmission rate is increased to above 100 Gb/s with higher-order modulation format, then transmission capacity is improved, but optical signal-to-noise ratio requirement increases which limits system transmission distance
Solution Approach 1:
The patent combines Raman amplification and EDFA into a hybrid amplification system. The Raman amplifier provides low-noise pre-amplification for high-speed signals, while the EDFA provides additional gain. This merged system achieves the required OSNR for 100 Gb/s and higher-order modulation formats over extended transmission distances
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enhances the reliability of the optical fiber communications system by preventing significant OSNR degradation and ensuring uninterrupted service even when all local-end pump lights fail, improving fault tolerance and reducing economic losses from service interruptions.
Implementation Method 1
An erbium doped fiber amplifier (EDFA) was used in a submarine cable optical repeater
Implementation Method 2
A distributed Raman amplification technology can provide a lower noise factor to improve the system OSNR
Data Source
AI summary
Embodiments of the present disclosure provide an optical repeater and an optical fiber communications system. An implementation solution of the optical repeater includes: a first input end of the optical repeater, a first output end of the optical repeater, a first erbium doped fiber, a first coupler, a second coupler, and a first pump light processing component, where the first input end of the optical repeater is connected to an input end of the first erbium doped fiber, an output end of the first erbium doped fiber is connected to an input end of the first coupler, a first output end of the first coupler is connected to a first input end of the second coupler, and an output end of the second coupler is connected to the first output end of the optical repeater.