Balanced Pumping L-Band Optical Fiber Amplifier Design
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Solution Overview
Problem
Conventional C-band optical path structures cause high noise figure, low conversion efficiency, and series non-linear four-wave mixing in L-band optical fiber amplifiers, leading to increased manufacturing costs.
Innovation Solution
A balanced pumping L-band optical fiber amplifier design featuring a first and second erbium-doped optical fiber with bidirectional pumping and an absorbing erbium-doped optical fiber to reduce noise and improve efficiency, using two pumping lasers for forward and backward pumping and an additional fiber to absorb amplified spontaneous emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional C-band optical path structure is used in L-band amplifier, then manufacturing cost is reduced, but noise figure increases and conversion efficiency decreases
Solution Approach 1:
The patent applies different pumping configurations to different erbium-doped fiber sections. The first EDF uses forward pumping while the second EDF uses backward pumping, optimizing each section's performance characteristics for the specific L-band application rather than using a uniform C-band configuration throughout.
Solution Approach 2:
The patent implements dynamic pumping power adjustment where the pumping power for the first EDF is set between 10-50mW and for the second EDF is set between 50-100mW. This dynamic optimization of pumping parameters resolves the contradiction by adapting power distribution to achieve both cost-effectiveness and low noise figure.
2Device complexity
If conventional C-band optical path structure is used in L-band amplifier, then device complexity is reduced, but conversion efficiency decreases
Solution Approach 1:
The patent divides the optical amplification function into two separate erbium-doped fiber sections with different pumping configurations. The first EDF (8-15m long) uses forward pumping while the second EDF (15-30m long) uses backward pumping. This segmentation allows each section to operate at optimal efficiency points, resolving the contradiction between simple structure and high conversion efficiency.
Solution Approach 2:
The patent changes key parameters including fiber length (8-30m range), pumping power (10-100mW range), and pumping direction (forward for first EDF, backward for second EDF). These parameter optimizations enable the system to achieve high conversion efficiency while maintaining relatively simple device structure.
3Reliability
If pumping power for first erbium-doped fiber is increased to reduce noise figure, then noise figure decreases, but manufacturing cost increases
Solution Approach 1:
The patent implements dynamic pumping power optimization where the first EDF receives 10-50mW and the second EDF receives 50-100mW. This balanced dynamic distribution achieves low noise figure without requiring excessive pumping power in a single fiber, thereby controlling manufacturing costs while maintaining reliability.
Solution Approach 2:
By segmenting the amplification function across two EDFs with different pumping powers, the system distributes the noise figure optimization burden. The first EDF with moderate pumping (10-50mW) contributes to noise reduction without requiring the high power that would increase manufacturing cost.
4Power
If pumping power for last erbium-doped fiber is increased to improve output power, then output power increases, but manufacturing cost increases
Solution Approach 1:
The patent applies dynamic pumping power optimization where the second EDF receives 50-100mW of backward pumping power. This optimized power level achieves the required output power improvement while avoiding the excessive cost increase that would result from uniformly high pumping across all fibers.
Solution Approach 2:
The patent applies backward pumping specifically to the second EDF where it is most needed for output power enhancement, while the first EDF uses forward pumping. This localized quality approach improves output power without unnecessarily increasing manufacturing cost across the entire system.
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 design significantly reduces noise figure, enhances conversion efficiency, and decreases manufacturing costs by applying bidirectional pumping and ASE absorption, effectively addressing the limitations of conventional C-band structures in L-band amplifiers.
Implementation Method 1
the at least two pumping lasers providing pumping light; wherein the first erbium-doped optical fiber is injected with forward pumping light and backward pumping light by the at least two pumping lasers
Implementation Method 2
the absorbing erbium-doped optical fiber without pumping light injection is arranged downstream of the second erbium-doped optica fiber to absorb amplified spontaneous emission (ASE) generated in the amplifier
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
The present invention relates to the field of optical communication, and particularly to a balanced pumping L-band optical fiber amplifier comprising a first erbium-doped optical fiber, a second erbium-doped optical fiber, an absorbing erbium-doped optical fiber and at least two pumping lasers, the first erbium-doped optical fiber, the second erbium-doped optical fiber and the absorbing erbium-doped optical fiber being sequentially arranged in this order, and the at least two pumping lasers providing pumping light; wrein the first erbium-doped optical fiber and the second erbium-doped optical fiber both are injected with forward pumping light and backward pumping light, and the absorbing erbium-doped fiber is arranged downstream of the second erbium-doped optical fiber to absorb amplified spontaneous emission (ASE) generated in the amplifier. In the present invention, bidirectional pumping is applied in the first and last erbium-doped fibers in the optical path, and an erbium-doped optical fiber that has no pumping injection is added to absorb the ASE. Thus, the pumping conversion efficiency is greatly improved, the nonlinear four-wave mixing effect is reduced, and the problem that the L-band optical fiber amplifier has a high noise when utilizing the backward pumping is solved. Meanwhile, the noise figure and the manufacturing cost of the amplifier are reduced.