Multi-Core Optical Amplifier for WDM Gain Equalization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical amplifiers face challenges in achieving high electric-power utilization efficiency due to inter-wavelength gain variations and high attenuation request levels, particularly in multi-core optical fiber amplifiers used in wavelength division multiplexing (WDM) systems.
Innovation Solution
The proposed optical amplifier employs a multi-core optical fiber with a clad and two cores doped with rare-earth ions, where a pumping light source supplies pumping light to the clad, and a wavelength demultiplexing mechanism separates and re-multiplexes signal light across the cores to equalize gain levels across different wavelengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional optical amplifier with single-core fiber is used, then the structure is simple, but inter-wavelength gain variations occur and electric-power utilization efficiency is low
Solution Approach 1:
The invention divides the optical fiber into multiple cores (first core and second core) within a single clad, allowing different wavelength bands to be amplified in different cores. This segmentation enables independent gain control for short and long wavelength bands, reducing inter-wavelength gain variations and improving electric-power utilization efficiency.
Solution Approach 2:
The invention transitions from a single-core fiber structure to a multi-core fiber structure, adding a spatial dimension for wavelength separation. By assigning different wavelength bands to different cores, the system achieves better gain equalization across wavelengths while maintaining the compact fiber structure.
2Productivity
If wavelength multiplexing is used to increase transmission capacity, then more wavelengths are amplified collectively, but gain deviation increases across wavelengths
Solution Approach 1:
The invention segments the WDM signal into different wavelength bands and routes them through different cores. The first core amplifies short wavelength bands while the second core amplifies long wavelength bands, allowing independent optimization of gain for each band and reducing overall gain deviation.
Solution Approach 2:
Different cores are optimized for different wavelength ranges, with each core having tailored doping concentrations and lengths to achieve optimal gain characteristics for its assigned wavelength band. This local optimization enables better overall gain equalization across the entire WDM spectrum.
3Reliability
If gain equalizing filters are added to reduce gain deviation, then transmission quality improves, but device complexity and attenuation request levels increase
Solution Approach 1:
The invention performs gain equalization at the amplification stage itself by using multiple cores with different gain characteristics, rather than requiring post-amplification filtering. This preliminary action prevents gain deviation before it affects transmission quality, eliminating the need for complex gain equalizing filters.
Solution Approach 2:
The multiple cores act as intermediaries that naturally provide gain equalization through their different amplification characteristics. Instead of using external filters to correct gain deviations, the cores themselves serve as the equalizing mechanism by having different gain profiles for different wavelength bands.
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 configuration reduces inter-wavelength gain variations, lowers attenuation request levels, and enhances electric-power utilization efficiency, enabling broadband and low-power consumption optical amplification.
Implementation Method 1
an optical fiber amplifier that amplifies a signal intensity of an optical signal, there is an optical fiber amplifier that amplifies, by inputting pumping light being output from a pumping light source to a rare-earth doped fiber to which the optical signal is input, a signal intensity of the optical signal
Implementation Method 2
activates erbium ions in an optical fiber by using pumping light of a 0.98-μm or 1.48-μm band, and uses laser transition of a 1.55-μm band possessed by erbium
Implementation Method 3
a wavelength demultiplexing means that separates a wavelength band of the wavelength multiplexed signal light propagating through the first core
Data Source
AI summary
The optical amplifier, which amplifies wavelength multiplexed signal light, comprises: a multi-core optical fiber which includes cladding and a first core and a second core disposed in the cladding, and which is doped with rare-earth ions; an excitation light source for supplying excitation light to the cladding of the multi-core optical fiber; and a wavelength demultiplexing means for separating the wavelength bands of the wavelength multiplexed signal light that has propagated through the first core. The signal light of a relatively long wavelength band among a plurality of wavelength bands separated by the wavelength demultiplexing means is caused to propagate through the second core, and is then multiplexed with the signal light of a relatively short wavelength band among the plurality of wavelength bands separated by the wavelength demultiplexing means, and the resultant multiplexed signal light is output.