Optical Semiconductor Device Current Distribution Optimization

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Solution Overview

Problem

High power semiconductor laser devices face challenges in achieving high optical output power while maintaining low drive voltage and high electrical-optical conversion efficiency due to the increased electrical resistance and heat generation from concentrated current paths, which limits their performance.

Innovation Solution

The semiconductor laser device is designed with an electrical connection region where the contact area on the second facet side is significant, allowing for a more even current distribution that matches the photon density distribution, reducing the drive voltage and increasing the optical output power.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If bonding wires are concentrated on the first facet side to match high photon density region, then optical output power increases, but drive voltage increases due to current concentration and electrical resistance

Engineering Contradiction:
Improveoptical output powerVSAvoiddrive voltage
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The patent applies local quality by creating different contact area densities in different regions of the electrical connection region. Specifically, the first region (corresponding to high photon density) has a first contact area density, while the second region (corresponding to low photon density) has a second contact area density that is different from the first. This non-uniform distribution optimizes carrier supply locally matching the photon density profile, resolving the contradiction between maximizing optical output and minimizing drive voltage.

Inventive Principle:
Principle #3Local quality

2Power

If bonding wires are evenly distributed, then current distribution is even, but optical output power is limited due to carrier insufficiency in high photon density regions

Engineering Contradiction:
Improveoptical output powerVSAvoidcurrent distribution uniformity
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The patent implements local quality by making the contact area density vary across different regions corresponding to different photon density levels. The first region with high photon density has a different contact area density compared to the second region with low photon density, creating a non-uniform current distribution that matches the optical field profile, thereby maximizing optical output power.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent applies parameter changes by varying the contact area density parameter across different regions of the electrical connection region. By changing this geometric parameter to match the photon density distribution, the patent optimizes carrier supply to achieve high optical output power without being constrained by uniform current distribution requirements.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If bonding wires are concentrated on the first facet side, then carrier supply to high photon density region improves, but electrical resistance increases due to heat generation

Engineering Contradiction:
Improvecarrier supply efficiencyVSAvoidelectrical resistance and heat generation
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent applies local quality by creating region-specific contact area densities that match the photon density profile. The first region corresponding to high photon density has a first contact area density, while the second region corresponding to low photon density has a second contact area density. This localized optimization improves carrier supply efficiency where needed while distributing current more effectively to reduce overall electrical resistance and heat generation.

Inventive Principle:
Principle #3Local quality

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 configuration effectively increases the optical output power while reducing the drive voltage and enhancing the electrical-optical conversion efficiency, addressing the limitations of previous designs by optimizing the current distribution within the active region.

Implementation Method 1

an active region interposed between a first facet on a light emitting side and a second facet opposing to the first facet

Methodology Applied
Scientific EffectStimulated emission: Laser

Implementation Method 2

bonding wires 2 of Au or the like are connected to an electrode layer of the semiconductor laser device 1 as an electrical connection region used for injecting a current

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3754799B1Optical semiconductor device
Publication Date: 2023.06.21 FURUKAWA ELECTRIC CO LTD
  • EP3754799B1 patent drawingFigure 1~3
  • EP3754799B1 patent drawingFigure 4A~4B
  • EP3754799B1 patent drawingFigure 5~6

AI summary

An optical semiconductor device includes: a semiconductor multilayer structure, an active region interposed between a first facet on a light emitting side and a second facet opposing to the first facet, and a first electrode layer provided on a top of the semiconductor multilayer structure and a second electrode layer provided on a bottom of the semiconductor multilayer structure; and an electrical connection region connected to at least one of the first electrode layer and the second electrode layer of the optical semiconductor device and used for injecting a current to the active region, and α > β and β > 0 are satisfied, where in a contact area between the electrical connection region and the optical semiconductor device, the contact area included in a half region on the first facet side in a top area of the optical semiconductor device is denoted as α, and the contact area included in a half region on the second facet side is denoted as β.