Semiconductor Laser Double Waveguide Facet Protection

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing semiconductor laser devices face catastrophic and gradual degradation issues at the mirror facets due to high power density radiation, with existing protection methods either failing to minimize absorption losses or introducing defects and complex processing requirements.

Innovation Solution

The implementation of a double waveguide structure with an active waveguide and a passive trapping waveguide, where the passive waveguide captures radiation near the mirror facet, reducing absorption losses and nonradiative recombination without disrupting the initial waveguide's propagation properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the active region is etched and replaced with other semiconductor material to protect the mirror facet, then the catastrophic degradation level is improved, but the waveguide is interrupted and diffraction losses increase

Engineering Contradiction:

Improvecatastrophic degradation levelVSAvoiddiffraction losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The laser device is divided into a main segment containing the active region and an end segment with the modified waveguide structure. This segmentation allows the protective function to be localized in the end segment without disrupting the active region in the main segment, thereby avoiding diffraction losses while maintaining protection against catastrophic degradation.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The waveguide structure is modified locally in the end segment adjacent to the mirror facet, while the main segment retains its original waveguide properties. This local modification creates a protective region with different optical properties (reduced absorption) without affecting the overall waveguide integrity and minimizing diffraction effects.

Inventive Principle:

Principle #3Local quality

2Loss of energy

If a narrow etching stripe is used to minimize diffraction losses, then the energy loss is reduced, but the manufacturing difficulty and regrowth complexity increase

Engineering Contradiction:

Improvediffraction lossesVSAvoidetching and regrowth process

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

Instead of etching through the entire waveguide structure, the invention applies partial action by modifying only the cladding layers in the end segment while leaving the core waveguide structure intact. This reduces the etching depth and complexity, making the manufacturing process more feasible while still achieving the protective function.

Inventive Principle:

Principle #16Partial or excessive action

3Ease of manufacture

If oxide layers are deposited on the mirror facet to protect it, then the processing is simpler, but the catastrophic degradation level is not sufficiently improved

Engineering Contradiction:

Improvedeposition processVSAvoidcatastrophic degradation level

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The invention uses a composite structure consisting of multiple semiconductor layers with different bandgap energies. The end segment employs materials with higher bandgap (such as AlGaAs with higher Al content) that are transparent to the laser wavelength, creating a composite material system that provides both protection against catastrophic degradation and optical transparency.

Inventive Principle:

Principle #40Composite materials

4Reliability

If the entire waveguide is affected by etching to replace material at the mirror facet, then the protection is achieved, but the waveguide interruption causes increased diffraction

Engineering Contradiction:

Improvemirror facet protectionVSAvoidwaveguide continuity

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

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 solution allows semiconductor laser devices to operate at high power densities with reduced absorption losses and nonradiative recombination, preserving the initial waveguide's optical properties and minimizing defect formation, thereby enhancing the resistance to catastrophic optical degradation.

Implementation Method 1

a coupled passive trapping waveguide

Methodology Applied

Scientific EffectOptical coupling:

Implementation Method 2

the second waveguide named also the passive trapping waveguide, and a second end segment with a similar layered structure which is formed between the main segment and an exit mirror facet

Methodology Applied

Scientific EffectRadiation capture: Absorption (EM radiation)

Data Source

PatentUS9912118B2Diode laser type device

Publication Date: 2018.03.06 PETRESCU PRAHOVA IULIAN BASARAB

AI summary

Semiconductor laser with mirror facet protection against degradation including a modified segment near the exit window that has a double waveguide with a reduced confinement factor compared with the confinement factor of the double waveguide of the main laser segment, such that the radiation at the exit facet in the modified double waveguide is pushed away from the active region, less radiation is absorbed at the facet and less heat is produced by nonradiative recombination at the exit facet, while the field distribution of the two double waveguides have a good overlap and low transfer losses due to the use of waveguide type structures with an active waveguide and a passive trapping waveguide.