VCSEL Cavity Control Structure for Stable Polarization and Power

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Solution Overview

Problem

Conventional vertical cavity surface emitting laser (VCSEL) devices face issues with low quality layers and defects due to the use of single deposition processes, which affect performance, manufacturability, and reliability, and struggle with mode stability and power output in three-dimensional sensing applications.

Innovation Solution

A multiphase growth sequence using MOCVD and MBE processes to form mirrors, active regions, and control structures, with the control structure formed during a transition period to provide mode control and confinement within the VCSEL cavity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a single deposition process (MOCVD or MBE) is used to form VCSEL layers, then the manufacturing process is simple, but the layer quality is low and defects occur

Engineering Contradiction:

Improvelayer qualityVSAvoiddeposition process

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the deposition process into two separate phases: MBE phase for forming the active region and spacer, and MOCVD phase for forming mirrors and control structures. This segmentation allows each process to be optimized for its specific function, achieving high layer quality without excessive overall complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The MBE phase performs preliminary formation of critical layers (active region and spacer) before the MOCVD phase. This preliminary action ensures that the most sensitive layers are created under optimal MBE conditions, preventing defects before subsequent MOCVD deposition.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If no control structure is incorporated in the VCSEL cavity, then the device structure is simple, but mode stability and polarization control are poor

Engineering Contradiction:

Improvemode stabilityVSAvoidcavity structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The control structure is formed locally within the VCSEL cavity using selective chemical etching during the transition period. This local modification provides mode control and polarization stability without requiring complex changes to the overall device structure.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The control structure acts as an intermediary element within the cavity that mediates between the simple VCSEL structure and the desired mode control function. It provides the necessary polarization control while maintaining overall structural simplicity.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Manufacturing precision

If the control structure is formed during the transition period between MBE and MOCVD phases, then additional process time is required, but layer quality and defect reduction are improved

Engineering Contradiction:

Improvelayer qualityVSAvoidprocess time

Core Design Contradiction:

Manufacturing precisionVSLoss of time

Solution Approach 1:

The chemical etching process to form the control structure is performed continuously during the transition period between MBE and MOCVD phases, without interrupting the overall manufacturing flow. This maintains continuous useful action while achieving high layer quality.

Inventive Principle:

Principle #20Continuity of useful action

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 multiphase growth sequence enhances the quality of VCSEL device layers, reduces defects, stabilizes polarization modes, and increases output beam power by incorporating the control structure within the cavity, improving performance and reliability.

Implementation Method 1

the active region and the spacer are formed using a molecular beam epitaxy (MBE) process during an MBE phase of the multiphase growth sequence

Methodology Applied

Scientific EffectMolecular beam epitaxy: Epitaxy

Implementation Method 2

the second mirror is formed using a metal-organic chemical vapor deposition (MOCVD) process during an MOCVD phase of the multiphase growth sequence

Methodology Applied

Scientific EffectMetal-organic chemical vapor deposition: Chemical Vapour Deposition

Implementation Method 3

the control structure is formed using a chemical etching process during a transition period between the MBE phase and the MOCVD phase of the multiphase growth sequence

Methodology Applied

Scientific EffectChemical etching:

Data Source

PatentUS12362541B2Methods for incorporating a control structure within a vertical cavity surface emitting laser device cavity

Publication Date: 2025.07.15 WELLS FARGO BANK NA

AI summary

A method of incorporating a control structure within a VCSEL device cavity using a multiphase growth sequence includes forming a first mirror over a substrate, forming an active region over the first mirror, forming a spacer on a surface of the active region, forming a control structure on a surface of the spacer, and forming a second mirror over the control structure. The active region and the spacer are formed using a molecular beam epitaxy (MBE) process during an MBE phase of the multiphase growth sequence. The second mirror is formed using a metal-organic chemical vapor deposition (MOCVD) process during an MOCVD phase of the multiphase growth sequence. The control structure is formed using a chemical etching process during a transition period between the MBE phase and the MOCVD phase of the multiphase growth sequence.