Mode-Demultiplexed Optical Power Equalization for Multi-Mode Pump Light
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Solution Overview
Problem
Current methods for power equalization of multi-mode pump light sources in erbium-doped fiber amplifiers (EDFAs) have poor precision and limited applicability due to the inability to directly apply multi-mode light and the need for manual adjustment of power in different modes.
Innovation Solution
An optical power adjustment system comprising a mode demultiplexer and an optical power adjustment apparatus with phase shifters and multi-mode interferometers (MMIs) that converts multi-mode optical signals into fundamental-mode signals, ensuring equal output power through precise phase adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a multi-mode pump light source is used to reduce cost, then the cost is reduced, but the power equalization precision deteriorates due to the inability to directly apply multi-mode light to EDFA
Solution Approach 1:
The patent segments the multi-mode optical signal into multiple single-mode signals through a mode demultiplexer. This segmentation allows each mode to be independently processed and power-adjusted, thereby achieving precise power equalization while maintaining the cost advantage of using multi-mode light sources.
Solution Approach 2:
The patent introduces a mode demultiplexer as an intermediary device between the multi-mode pump light source and the EDFA. This intermediary converts multi-mode light into separable single-mode signals, enabling precise power control of each mode before recombination, thus resolving the precision issue while keeping the light source cost-effective.
2Ease of operation
If a scrambler is used to equalize power in different modes, then power equalization is achieved, but the adjustment precision deteriorates due to poor precision in bending fibers or other manners
Solution Approach 1:
The patent replaces the mechanical fiber bending method with an optical interference-based phase adjustment system. By using phase shifters to control the phase of optical signals and relying on constructive and destructive interference in MMIs, the system achieves precise power control without mechanical manipulation, significantly improving adjustment precision.
Solution Approach 2:
The patent changes the control parameter from mechanical fiber bending to optical phase modulation. By adjusting the phase parameter of optical signals through phase shifters, the system achieves precise control over power distribution among modes, replacing imprecise mechanical adjustments with accurate electrical control of optical parameters.
3Ease of operation
If manual power adjustment is performed on mode demultiplexed signals, then power equalization is attempted, but the applicability deteriorates when there are a large quantity of fundamental-mode optical signals
Solution Approach 1:
The patent merges multiple single-mode signals through constructive interference in multi-mode interferometers (MMIs) to produce a smaller number of output signals with equalized power. This combining approach reduces the number of individual adjustment operations needed, making the system scalable and applicable to a large quantity of fundamental-mode optical signals.
Solution Approach 2:
The patent creates a universal power equalization system based on optical interference principles that can handle any number of input modes. The MMI-based architecture provides multi-functionality, allowing the same mechanism to equalize power across different numbers of modes by simply adjusting the configuration, thereby improving applicability to various signal quantities.
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
The system achieves higher precision and wider applicability in power equalization of fundamental-mode optical signals, enabling efficient use of multi-mode pump light sources in EDFAs by ensuring consistent power output across multiple single-mode fibers.
Implementation Method 1
A Kth optical power adjustment module in the optical power adjustment apparatus includes 2K−1 multi-mode interferometers MMIs
Implementation Method 2
Each optical power adjustment module includes a plurality of phase shifters, and the control apparatus is electrically connected to the M optical power adjustment modules
Data Source
AI summary
Embodiments of this application provide an optical power adjustment system and an optical power adjustment apparatus. The system includes a multi-mode light source, a mode demultiplexer, and an optical power adjustment apparatus. The multi-mode light source is configured to output a multi-mode optical signal, where the multi-mode optical signal includes N transverse-mode optical signals, N=2M, and M is an integer greater than 1. The mode demultiplexer is configured to convert the N transverse-mode optical signals into N fundamental-mode optical signals, and output the N fundamental-mode optical signals. The optical power adjustment apparatus includes M optical power adjustment modules and a control apparatus, each optical power adjustment module includes a plurality of phase shifters, and the control apparatus is electrically connected to the M optical power adjustment modules. A Kth optical power adjustment module includes 2K−1 multi-mode interferometers MMIs.