Bidirectional Raman Amplifier Disconnection Detection
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Solution Overview
Problem
Existing bidirectional Raman amplification systems face challenges in accurately detecting transmission line disconnection due to wide bandwidths of excitation lights, leading to incorrect detection and failure in cutting off excitation lights when line disconnection occurs.
Innovation Solution
The implementation of a bidirectional Raman amplification device with a first Raman amplifier and a second Raman amplifier, each equipped with optical filters and detectors, where the first Raman amplifier stops output when detecting higher power from reflected light and the second Raman amplifier stops output when power reduction is detected from transmitted light, effectively cutting off excitation lights during line disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the bandwidth of excitation light is widened to improve amplification efficiency, then amplification efficiency is improved, but detection precision of transmission line disconnection deteriorates
Solution Approach 1:
The patent divides the detection function into two separate detection paths: one for detecting the backward propagating light (using a first optical filter and first detector) and another for detecting the forward propagating light (using a second optical filter and second detector). This segmentation allows each detection path to be optimized independently, enabling precise disconnection detection even with wide bandwidth excitation light by comparing signals from both directions.
2Productivity
If bidirectional Raman amplification is implemented to improve signal amplification, then amplification performance is improved, but reliability of disconnection detection deteriorates
Solution Approach 1:
The patent introduces optical filters as intermediary components in each detection path. The first optical filter extracts backward propagating light while blocking forward excitation light, and the second optical filter extracts forward propagating light while blocking backward excitation light. These intermediary filters enable reliable disconnection detection in the bidirectional amplification system by isolating the detection signals from the amplification signals.
3Duration of action of stationary object
If excitation light is continuously output to maintain amplification, then amplification continuity is improved, but harmful effects from line disconnection increase
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the detection signals from both optical detectors. When disconnection is detected (indicated by abnormal signal levels in the detection paths), the control unit immediately shuts down the excitation light sources. This feedback loop maintains amplification continuity during normal operation while automatically preventing optical power leakage when line disconnection occurs.
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 enables accurate detection and shutdown of both forward and backward excitation lights during transmission line disconnection, preventing signal interference and improving amplification efficiency by minimizing relative intensity noise.
Implementation Method 1
a first optical filter configured to cut off the second wavelength band from the second excitation light and/or a first reflected light of the first excitation light, which are input from the transmission line
Implementation Method 2
a technique of detecting transmission line disconnection on the basis of a reflected light of when an excitation light output from a Raman amplifier performs Fresnel reflection due to the transmission line disconnection
Implementation Method 3
A Raman amplifier amplifies a signal light using a transmission line through which the signal light is transmitted as an amplification medium by outputting excitation light having a wavelength band on a shorter wavelength side than the signal light to the transmission line
Data Source
AI summary
An optical amplification device includes a first Raman amplifier outputs a first excitation light to a transmission line in a same direction as a signal light, and a second Raman amplifier outputs a second excitation light to the transmission line in an opposite direction to the signal light. The first Raman amplifier includes a first detector detects a first power of a first transmitted light transmitted through a first optical filter. The second Raman amplifier includes a second detector detects second power of a second transmitted light transmitted through a second optical filter. The first Raman amplifier stops output of the first excitation light when the first power is higher than a threshold. The second Raman amplifier stops output of the second excitation light when the second power is reduced from power of the first excitation light transmitted through the second optical filter.