Monolithic SOA VOA Optical Amplifier With Moveable Waveguide

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Solution Overview

Problem

Current optical amplifier devices are too large and expensive due to the use of separately packaged semiconductor optical amplifier (SOA) and variable optical attenuator (VOA) components, limiting their ability to operate over longer distances and wider input power ranges without forward error correction (FEC).

Innovation Solution

A monolithic SOA/VOA device with a variable degree of optical coupling between waveguides, allowing for adjustable light amplitude and gain, achieved through a moveable waveguide that can be bent or displaced to alter coupling, and controlled by electrostatic or thermal means, integrated on a single substrate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If separately packaged SOA and VOA components are used, then the device can achieve amplification and attenuation functions, but the module size increases and cost increases

Engineering Contradiction:
Improvefunctional capabilityVSAvoidmodule size
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent combines the SOA and VOA functions into a single monolithic semiconductor device structure. The optical amplifier section and variable optical attenuator section are integrated on the same substrate with shared waveguides and facets, eliminating the need for separate packaging of two distinct components while maintaining both amplification and attenuation capabilities.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated device structure serves multiple functions simultaneously. The same optical path and waveguide structure support both the amplification function (through the SOA section with bias current) and the attenuation function (through the VOA section with variable coupling), making the device versatile for different operational requirements without needing separate specialized components.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If separately packaged SOA and VOA components are used, then the device can achieve amplification and attenuation functions, but the manufacturing cost increases

Engineering Contradiction:
Improvefunctional capabilityVSAvoidmanufacturing cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

By merging the SOA and VOA into a single monolithic device, the patent reduces manufacturing complexity. The device can be fabricated using standard semiconductor processing techniques in a single production run, eliminating the need for separate fabrication, packaging, and assembly processes for two distinct components, thereby reducing overall manufacturing cost.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The device is segmented into functional sections (optical amplifier section and variable optical attenuator section) within a single integrated structure. This segmentation allows each function to be optimized independently in the design phase while maintaining a unified manufacturing process, balancing functional requirements with manufacturing efficiency.

Inventive Principle:
Principle #1Segmentation

3Volume of moving object

If a monolithic SOA/VOA device is used, then the module size is reduced and cost is reduced, but the input power range control becomes more challenging

Engineering Contradiction:
Improvemodule sizeVSAvoidcontrol mechanism complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The patent employs a moveable waveguide structure that can dynamically adjust its position relative to the optical amplifier. This dynamic adjustment mechanism allows real-time control of the input power range by varying the coupling between the moveable waveguide and the optical amplifier, providing flexibility in power management despite the integrated compact structure.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The moveable waveguide acts as an intermediary element between the input optical signal and the optical amplifier. By controlling the position and coupling of this intermediate waveguide, the system can regulate the input power level to the amplifier without requiring direct control of the amplifier itself, simplifying the overall control architecture.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Adaptability or versatility

If the first waveguide is made moveable to alter coupling, then the optical coupling can be adjusted, but the device complexity increases

Engineering Contradiction:
Improvecoupling adjustabilityVSAvoidstructural complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical actuation systems with electrostatic actuation for moving the waveguide. The electrostatic element generates electrostatic force to position the moveable waveguide, eliminating the need for mechanical motors, gears, or other complex mechanical components, thereby reducing overall device complexity while maintaining coupling adjustability.

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

Solution Approach 2:

The system controls optical coupling by changing the positional parameter of the moveable waveguide rather than altering the fundamental structure or materials. By adjusting the distance and alignment parameters of the waveguide relative to the optical amplifier, the coupling strength can be varied continuously without modifying the basic device architecture.

Inventive Principle:
Principle #35Parameter changes

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

Enables compact modules to operate over 0 to 40km without FEC or 80km with FEC, while maintaining a wide dynamic range of input powers, reducing size and cost by integrating optical amplifier and coupling elements on a single substrate.

Implementation Method 1

Varying the degree of optical coupling between the input port and the optical amplifier provides an effective way of varying the amplitude of the light that enters the optical amplifier

Methodology Applied
Scientific EffectOptical coupling: Waveguide (optics)

Implementation Method 2

the first waveguide may be moveable under electrostatic force and the optical amplifier device may comprise an electrostatic element for exerting an electrostatic force on the first waveguide

Methodology Applied
Scientific EffectElectrostatic force: Electrostatics

Implementation Method 3

the first waveguide may be moveable under the action of heat and the optical amplifier device may comprise a heater for heating the first waveguide

Methodology Applied
Scientific EffectThermal action: Heating

Implementation Method 4

The bias current supplied to the device can be controlled so that there is gain along the cavity by stimulation of the active region of the device, resulting in amplification

Methodology Applied
Scientific EffectStimulation of active region: Light Emitting Diode

Data Source

PatentEP3648267B1Optical amplifier
Publication Date: 2022.05.11 HUAWEI TECH CO LTD
  • EP3648267B1 patent drawingFigure 1~2
  • EP3648267B1 patent drawingFigure 3~4
  • EP3648267B1 patent drawingFigure 5~6

AI summary

An optical amplifier device, the device comprising: an input port for receiving an optical signal; an optical amplifier for amplifying a signal input to the optical amplifier to form an amplified signal at an output of the optical amplifier device; an optical path for conveying an optical signal from the input port to the optical amplifier, the optical path comprising a passive optical coupling element which is variable to alter the degree of optical coupling between the input port and the optical amplifier to thereby alter the gain of the optical amplifier device.