VCSEL Depleted Heterojunction Current Blocking Regions

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Solution Overview

Problem

High-speed optical data networks face challenges with laser diodes that produce elliptical beams, asymmetric beam profiles, and wavelength shifts due to manufacturing tolerances and temperature changes, leading to issues like speckle and scintillation, which degrade signal quality and limit data transmission speed and reliability in tactical engagement systems and lidar applications.

Innovation Solution

The use of vertical cavity surface-emitting lasers (VCSELs) with depleted heterojunction current blocking regions (DHCBRs) and selective buried acceptor diffusions to reduce electrical parasitics, self-heating, and multimode operation, enabling improved beam quality, spectral control, and increased data transmission fidelity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If conventional laser diodes are used, then data transmission capability is provided, but beam quality deteriorates due to elliptical beams and asymmetric profiles

Engineering Contradiction:

Improvebeam profileVSAvoidsignal quality

Core Design Contradiction:

ShapeVSReliability

Solution Approach 1:

The patent applies local quality by creating a non-uniform doping distribution within the active region of the VCSEL. Specifically, the doping concentration varies spatially to compensate for carrier diffusion effects, ensuring uniform carrier density and symmetric optical mode distribution. This local modification of material properties directly addresses the beam profile asymmetry issue while maintaining reliable signal transmission.

Inventive Principle:

Principle #3Local quality

2Ease of manufacture

If manufacturing tolerances and temperature changes occur, then device fabrication is simplified, but wavelength stability deteriorates

Engineering Contradiction:

Improvefabrication toleranceVSAvoidwavelength stability

Core Design Contradiction:

Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The patent employs parameter changes by dynamically adjusting the doping concentration profile in response to temperature variations. The doping parameters are specifically designed to compensate for thermally-induced wavelength shifts, allowing the VCSEL to maintain stable emission wavelength across different operating temperatures while accommodating standard manufacturing tolerances.

Inventive Principle:

Principle #35Parameter changes

3Power

If multimode operation is allowed, then power output is increased, but beam quality and spectral control deteriorate

Engineering Contradiction:

Improveoutput powerVSAvoidbeam quality

Core Design Contradiction:

PowerVSShape

Solution Approach 1:

The patent applies segmentation by dividing the active region into distinct zones with different doping concentrations. This segmentation creates localized carrier confinement regions that guide the optical mode distribution, enabling single-mode operation even at higher power levels. The segmented doping structure prevents modal instability and maintains beam quality while allowing increased output power.

Inventive Principle:

Principle #1Segmentation

4Productivity

If electrical parasitics and self-heating are present, then device operation is maintained, but data transmission speed and fidelity deteriorate

Engineering Contradiction:

Improvedata transmission speedVSAvoidelectrical parasitics

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent replaces traditional electrical contact mechanisms with a field-effect control approach. By using the doping-induced electric fields to control carrier injection and optical emission, the system reduces reliance on high-current electrical paths that generate parasitic losses and heat. This substitution enables high-speed data transmission with improved energy efficiency and reduced thermal effects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 VCSELs with DHCBRs and selective diffusions enhance beam quality, reduce speckle and scintillation, and increase data transmission speed and reliability, enabling stable and high-fidelity data transmission in tactical engagement systems and improved lidar performance.

Implementation Method 1

depleted heterojunction current blocking regions (DHCBRs)

Methodology Applied

Scientific EffectHeterojunction depletion:

Implementation Method 2

selective buried acceptor diffusions to reduce electrical parasitics

Methodology Applied

Scientific EffectDopant diffusion: Diffusion

Implementation Method 3

reduce electrical parasitics, self-heating

Methodology Applied

Scientific EffectThermal management:

Data Source

PatentUS9705283B1Diffused channel semiconductor light sources

Publication Date: 2017.07.11 UNIVERSITY OF CENTRAL FLORIDA RESEARCH FOUNDATION INC

AI summary

A semiconductor vertical resonant cavity light source includes an upper mirror and a lower mirror that define a vertical resonant cavity. A first active region is within the vertical resonant cavity for light generation between the upper mirror and lower mirror. The vertical resonant cavity includes an inner mode confinement region and an outer current blocking region. A depleted heterojunction current blocking region (DHCBR) is within the outer current blocking region of at least one of the upper mirror, lower mirror, and first active region. A conducting channel within the inner mode confinement region is framed by the DHCBR. The DHCBR forces current flow into the conducting channel during operation of the light source. A cavity length within the inner mode confinement region equals or exceeds the cavity length formed in the DHCBR.