Photovoltaic Cells in Optical Fibers for Remote Amplifier Powering

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Solution Overview

Problem

The attenuation coefficient of silica at 850 nm is much higher than at 1550 nm, limiting the distance that Remote Optically Pumped Amplifiers (ROPA) can be placed from the end of an optical fiber, which restricts the effective length of optical fibers before amplification is required.

Innovation Solution

Integrating Photovoltaic (PV) cells within optical fibers to convert scattered light into electricity, which can power remote optical amplifiers, thereby extending the distance over which optical signals can be transmitted without degradation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If Remote Optically Pumped Amplifiers (ROPA) are used to amplify optical signals, then the optical signal power is maintained, but the high attenuation coefficient of silica at 850 nm limits the distance amplifiers can be placed from the signal source

Engineering Contradiction:
Improveoptical signal qualityVSAvoiddistance between amplifier and signal source
Core Design Contradiction:
ReliabilityVSLength of stationary object

Solution Approach 1:

The patent converts the harmful scattered light that would normally be lost to absorption into a useful power source. By placing photovoltaic cells around the optical fiber, the scattered light at 850 nm is captured and converted to electrical energy, which then powers the ROPA amplifier, enabling it to operate at greater distances from the signal source.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The system becomes self-powered by harvesting its own waste energy. The optical fiber system generates scattered light during normal operation, and this scattered light is captured by photovoltaic cells to generate the power needed for amplification, creating a self-sustaining system that eliminates the need for external power sources at remote locations.

Inventive Principle:
Principle #25Self-service

2Power

If pump light is conveyed from the end of the optical fiber to power ROPAs, then amplification is achieved, but the high attenuation at 850 nm requires amplifiers to be placed close to the end, limiting the effective fiber length

Engineering Contradiction:
Improvepump power at active optical fiberVSAvoideffective length of optical fiber
Core Design Contradiction:
PowerVSLength of stationary object

Solution Approach 1:

Instead of relying on pump light conveyed from the end of the fiber (which suffers from high attenuation), the system converts the previously wasted scattered light into electrical power. This allows ROPAs to be powered locally at any position along the fiber, extending the effective fiber length beyond what is possible with traditional remote pumping from the end.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent replaces the optical pumping mechanism (which requires high-power light transmission through the fiber) with an electrical power system generated locally from scattered light. This substitution enables amplifiers to operate independently of the optical signal power, allowing them to be positioned much farther from the signal source.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If scattered light from the core is absorbed by protective material, then the fiber structure is protected, but useful power for remote amplification is lost

Engineering Contradiction:
Improvefiber protectionVSAvoidscattered light energy
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The patent transforms the energy that would otherwise be wasted and absorbed by the protective material into a valuable power source. Photovoltaic cells are positioned to capture scattered light before it is absorbed, converting it to electrical energy that powers remote amplifiers, while the fiber structure maintains its protective function.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

Instead of allowing scattered light to be discarded through absorption by protective material, the system recovers this energy by capturing it with photovoltaic cells. The scattered light is converted to electrical power, which is then used to sustain remote amplification, turning a loss into a resource.

Inventive Principle:
Principle #34Discarding and recovering

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 use of PV cells within optical fibers enables remote powering of amplifiers, reducing the need for close proximity of amplifiers to the signal source, thus extending the effective length of optical fibers and maintaining signal quality.

Implementation Method 1

Integrating Photovoltaic (PV) cells within optical fibers to convert scattered light into electricity

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Implementation Method 2

an outer cladding surrounding the inner cladding that redirects scattered light from the core into the inner cladding

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 3

The transparent cladding has a lower index of refraction than the core, which keeps the optical signals mostly confined to the core due to total internal reflection

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP3503315B1Remote optical amplifiers powered by scattered light
Publication Date: 2020.08.12 THE BOEING CO
  • EP3503315B1 patent drawingFigure 1~2
  • EP3503315B1 patent drawingFigure 3
  • EP3503315B1 patent drawingFigure 4~5

AI summary

Optical fibers are described that include integrated Photovoltaic (PV) cells. The PV cells do not interfere with the optical signals that are transmitted along a core of an optical fiber. Further, the PV cells are able to convert light scattered from the core of the optical fiber into electricity. The PV cells may then be used to power remote optical amplifiers disposed along the optical fiber. For instance, the PV cells may be used to supplement or fully power the remote optical amplifiers. In one implementation, an apparatus includes an optical fiber and a PV cell. The optical fiber includes a first length and a second length that that are joined together at a splice. The optical fiber includes a core that conveys light, an inner cladding surrounding the core that is optically transparent, and an outer cladding surrounding the inner cladding that redirects scattered light from the core into the inner cladding. The PV cell is disposed at the splice between the first length and the second length of the optical fiber and includes a void that allows light from the core to traverse across the splice.