Locally Powered Optical Network for Submarine Cable Capacity
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Solution Overview
Problem
Conventional transoceanic fiber optic cables face limitations due to limited power and bandwidth, primarily because the power feeding equipment located onshore results in significant voltage drops along copper cables, restricting the number of Erbium Doped Fiber Amplifiers (EDFAs) and thus the capacity of submarine cables.
Innovation Solution
Implementing a locally powered optical communication network where power sources are placed along the communication trunk near the ocean surface, powering intermediate units that include lasers and optical combiners or amplifiers, enabling efficient Raman amplification and increasing the number of fiber pairs supported.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power is fed from onshore power sources through copper cables to repeaters, then repeaters can be powered, but significant voltage drops occur resulting in heat dissipation and limited capacity
Solution Approach 1:
The patent divides the power delivery system into segments by placing multiple power sources along the communication trunk at ocean surface locations, rather than relying on a single onshore power source. This segmentation allows power to be delivered locally to intermediate units, reducing the distance current must travel through copper cables and minimizing voltage drops and heat dissipation.
Solution Approach 2:
The patent introduces intermediate units as mediators between the power sources and repeaters. These intermediate units receive power from local power sources and distribute it to multiple repeaters, enabling efficient power delivery without requiring long copper cable runs from onshore sources. The intermediate units act as local power distribution hubs that reduce energy loss.
2Reliability
If voltage drop per repeater is limited to below 50V to ensure reliable operation, then repeaters can function reliably, but the number of fiber pairs supported is limited to 10-12
Solution Approach 1:
The patent segments the cable system into multiple independently powered sections, each with its own power source and intermediate unit. This allows each section to support more fiber pairs without being constrained by the 50V drop limit from a single onshore source, as each segment has its own local power supply that can deliver sufficient voltage to all repeaters within that segment.
Solution Approach 2:
The patent transitions from a single-dimension power delivery model (one onshore source to all repeaters) to a multi-dimensional model with power sources distributed along the ocean surface. This dimensional change allows simultaneous power delivery to multiple repeaters in parallel, effectively increasing the number of fiber pairs that can be supported while maintaining voltage requirements.
3Productivity
If more EDFAs are added to increase capacity, then signal amplification improves, but power requirements exceed what can be delivered from onshore sources
Solution Approach 1:
The patent divides the cable into multiple powered sections, each capable of supporting its own set of EDFAs. This segmentation removes the overall power limitation from a single onshore source, allowing each segment to be equipped with sufficient amplification capacity independent of the others, thereby increasing total system capacity.
Solution Approach 2:
The patent changes the power delivery parameters by introducing local power sources that can deliver higher voltages and currents to intermediate units, which then distribute power to multiple repeaters. This parameter change enables the system to support the power requirements of numerous EDFAs that would be impossible to power from distant onshore sources due to copper cable losses.
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 increases the capacity of transoceanic submarine cables by allowing multiple more fiber pairs to be supported, extending the reach of optical communications and overcoming signal attenuation, while simplifying maintenance and upgrade processes.
Implementation Method 1
Each submarine repeater comprises multiple Erbium Doped Fiber Amplifiers (EDFA), one amplifier for the signal in each direction of each fiber. Each EDFA has a gain sufficient to compensate for the loss experienced by the signal during its propagation in the previous section of fiber.
Implementation Method 2
Assuming highly efficient conversion from electrical into optical of 30% in diode laser and 10% efficiency of EDFA pumped by diode laser
Data Source
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AI summary
An optical system (100) for a locally powered optical communication network includes a first trunk terminal (110) emitting an optical signal (105, 105 c), a second trunk terminal (120) receiving the optical signal, a communication trunk (102, 102c), an intermediate unit (151) and a power source (160). The communication trunk is disposed along a floor of a body of water and couples the first trunk terminal to the second trunk terminal. The communication trunk transmits the optical signal from the first trunk terminal to the second trunk terminal. The intermediate unit is connected to the communication trunk between the first and second trunk terminals. The intermediate unit receives the emitted optical signal from the first trunk terminal, amplifies the received optical signal and sends the amplified optical signal to the second trunk. The power source powers the intermediate.