Shared Pump Optical Amplifier with PLC VOAs

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Solution Overview

Problem

The high cost and mechanical size of single channel Erbium Doped Fibre Amplifiers (EDFAs) in WDM systems increase with channel load due to the need for multiple discrete laser pumps and fixed footprints, which is not cost-effective for high channel load optical networks.

Innovation Solution

A high power pump laser is shared among multiple single channel EDFAs, with Variable Optical Attenuators (VOAs) integrated in a Planar Lightwave Circuit (PLC) configuration to control pump power independently for each channel, reducing the number of pumps and mechanical size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple discrete laser pumps are used for each single channel EDFA, then each channel can be amplified independently, but the cost and device complexity increase proportionally with channel load

Engineering Contradiction:

Improveindependent channel amplificationVSAvoidnumber of laser pumps

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple single-channel EDFAs are merged into a common pump chamber and shared among all channels. The patent combines several EDFAs (e.g., EDFAs 1-4) into a single physical unit with a shared pump laser, allowing one pump to serve multiple channels simultaneously. This merging reduces the total number of pump lasers from N (for N channels) to a smaller number of shared pumps, directly addressing the device complexity issue while maintaining independent channel amplification capability.

Inventive Principle:

Principle #5Merging (Combining)

2Device complexity

If a high power pump laser is shared among multiple EDFAs, then the number of pumps is reduced, but the pump power must be strongly increased

Engineering Contradiction:

Improvenumber of pump lasersVSAvoidpump laser power

Core Design Contradiction:

Device complexityVSPower

Solution Approach 1:

The shared pump laser output is segmented and distributed to multiple EDFAs through individual pump coupling units. Each EDFA receives a portion of the total pump power through optical coupling mechanisms (such as couplers or splitters), allowing the high power pump to be divided into multiple lower power streams that can effectively pump multiple EDFAs simultaneously. This segmentation enables one high-power pump to replace multiple lower-power pumps.

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If discrete components are used for each amplifier, then individual channel control is achieved, but the mechanical footprint increases proportionally with channel load

Engineering Contradiction:

Improveindividual channel controlVSAvoidamplifier footprint

Core Design Contradiction:

Adaptability or versatilityVSArea of stationary object

Solution Approach 1:

Multiple EDFAs are nested within a common pump chamber, creating a compact multi-functional unit. The patent implements a nested structure where several EDFA modules (each capable of independent channel control) are housed within a single shared amplifier unit that shares common components such as the pump laser, control electronics, and housing. This nesting approach allows individual channel control while dramatically reducing the total mechanical footprint compared to discrete amplifiers for each channel.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 approach significantly reduces amplification costs and footprint while maintaining efficient power management, allowing for compact and cost-effective optical amplification in high channel load networks.

Implementation Method 1

Erbium Doped Fibre Amplifiers (EDFAs) are widely deployed in optical Dense Wavelength Division Multiplexing (DWDM) transmission systems due to their capability to amplify all signals of a DWDM (Dense wavelength Division Multiplex) signal simultaneously in an almost ideal manner

Methodology Applied

Scientific EffectStimulated emission:

Implementation Method 2

by the laser pumps, that provide the power to allow that a sufficient part of the dopant ions in the Erbium Doped Fibre (EDF) leave the ground state to reach the desired excited state level

Methodology Applied

Scientific EffectLaser pumping: Laser

Implementation Method 3

The amplifier arrangement comprises a first circulator (101) which is configured to direct an input signal (102) from an input port (103) to a first output port (104) and to direct an output signal (105) from a second output port (106) to a feedback port (107)

Methodology Applied

Scientific EffectOptical circulator:

Implementation Method 4

The pump signal is distributed by an optical splitter and fed to the amplifiers

Methodology Applied

Scientific EffectOptical splitting:

Implementation Method 5

Variable Optical Attenuators (VOAs) integrated in a Planar Lightwave Circuit (PLC) configuration to control pump power independently for each channel

Methodology Applied

Scientific EffectOptical attenuation: Absorption (EM radiation)

Data Source

PatentEP2131509B1Optical amplifier arrangement

Publication Date: 2014.08.06 XIEON NETWORKS SARL

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AI summary

An optical amplifier arrangement for WDM systems (wavelength division multiplex) uses a common pump source (PSo) connected to an input of an splitter (SP) deploying pump light via variable optical attenuators (VOA1 - VOAn) to a plurality of optical amplifiers (A1 - An). Control circuits (C1 - Cn) determine individually the output powers of the amplifiers (A1 - An) by varying the attenuations of the variable optical attenuators (VOA1 - VOAn). Amplifier units based on PLC technology are implemented to reduce the size.