Hermetic Swept Source Package with Oxygen Atmosphere

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Solution Overview

Problem

Swept sources for Optical Coherence Tomography (OCT) systems, particularly tunable lasers and filtered amplified spontaneous emission (ASE) sources, experience packaging-induced failures (PIF) due to high optical power densities within the devices, leading to hydrocarbon breakdown and corrosion, even at low output powers.

Innovation Solution

Hermetically sealing dry oxygen or ozone within the package to prevent hydrocarbon breakdown, combined with moisture and hydrogen getters to minimize internal corrosion, and using a hermetic package with an optical bench to house the semiconductor gain medium and tunable filter, ensuring the atmosphere absorbs carbon species and reduces moisture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If high optical power density is used within the swept source device, then imaging resolution and speed are improved, but packaging-induced failures occur due to hydrocarbon breakdown and corrosion

Engineering Contradiction:

Improveimaging resolutionVSAvoiddevice reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the conventional inert atmosphere (nitrogen or dry air) with an oxygen-rich atmosphere (20-80% oxygen) inside the hermetic package. This counterintuitive approach prevents hydrocarbon breakdown by maintaining a controlled oxidative environment that stabilizes the organic materials within the package, thereby preventing the packaging-induced failures that occur under high optical power density while preserving imaging resolution

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

Solution Approach 2:

The patent changes the chemical composition parameter of the internal atmosphere from conventional inert gases to oxygen-rich mixtures. This parameter change fundamentally alters the chemical stability of organic materials within the package, preventing hydrocarbon decomposition even under high optical power conditions, thus resolving the contradiction between imaging performance and device reliability

Inventive Principle:

Principle #35Parameter changes

2Reliability

If hermetic sealing with oxygen is implemented, then hydrocarbon breakdown is prevented, but oxidation of internal components may occur

Engineering Contradiction:

Improvepackage reliabilityVSAvoidoxidation damage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent optimizes the oxygen concentration parameter to a specific range (20-80%) rather than using pure oxygen. This parameter optimization prevents hydrocarbon breakdown while minimizing excessive oxidation of metal components, achieving a balance between preventing packaging-induced failures and protecting against oxidation damage

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent uses composite atmospheric composition combining oxygen with other gases (creating a gas mixture rather than pure oxygen). This composite approach provides the benefits of oxygen-rich environment for preventing hydrocarbon breakdown while the other gas components help mitigate excessive oxidation of internal metal components

Inventive Principle:

Principle #40Composite materials

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 solution effectively prevents packaging-induced failures by controlling internal gas composition and moisture levels, enhancing the reliability and longevity of OCT swept sources even at low output powers, thereby reducing motion-induced artifacts and improving imaging resolution.

Implementation Method 1

dry oxygen, or other gases such as ozone, is sealed within the hermetic package of the external cavity laser or ASE swept source to avoid packaging-induced failure (PIP). PIF due to hydrocarbon breakdown at optical interfaces with high power densities

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

Hermetically sealing dry oxygen or ozone within the package to prevent hydrocarbon breakdown, combined with moisture and hydrogen getters to minimize internal corrosion

Methodology Applied

Scientific EffectHermetic sealing: Physical Containment

Implementation Method 3

combined with moisture and hydrogen getters to minimize internal corrosion

Methodology Applied

Scientific EffectAdsorption: Adsorption

Data Source

PatentUS9048614B2Method and system for avoiding package induced failure in swept semiconductor source

Publication Date: 2015.06.02 EXCELITAS TECHNOLOGIES CORP

AI summary

Dry oxygen, dry air, or other gases such as ozone are hermetically sealed within the package of the external cavity laser or ASE swept source to avoid packaging-induced failure or PLF. PIF due to hydrocarbon breakdown at optical interfaces with high power densities is believed to occur at the SLED and/or SOA facets as well as the tunable Fabry-Perot reflector/filter elements and/or output fiber. Because the laser is an external cavity tunable laser and the configuration of the ASE swept sources, the power output can be low while the internal power at surfaces can be high leading to PIF at output powers much lower than the 50 mW.