Quantum Well Intermixed Laser Stripes for Wide Wavelength Coverage

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Solution Overview

Problem

Existing semiconductor laser systems require multiple epitaxial wafers to achieve a wide range of wavelengths, increasing complexity and cost, as each laser chip must be grown and engineered separately to emit light across different wavelength ranges, which is inefficient.

Innovation Solution

A semiconductor laser chip with multiple laser stripes is developed, where the optical gain profile of each stripe is shifted using a quantum well intermixing process, allowing multiple stripes to emit different wavelengths from a single epitaxial wafer, reducing the need for multiple wafers and complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple laser chips are used to achieve wide wavelength range emissions, then the wavelength coverage is improved, but the system size, cost, and complexity increase

Engineering Contradiction:

Improvewavelength coverageVSAvoidsystem complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Multiple laser stripes with different emission wavelengths are integrated onto a single laser chip substrate. The chip includes a plurality of laser stripes where each stripe emits at a different wavelength, combining multiple laser functions into one device and eliminating the need for multiple separate laser chips

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A single laser chip is designed to perform multiple wavelength emission functions simultaneously. The chip structure supports multiple laser stripes that can emit across a wide wavelength range, making the chip a multi-functional device capable of serving various applications requiring different wavelengths

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If multiple epitaxial wafers are used to create laser stripes with different wavelengths, then the wavelength diversity is improved, but the manufacturing cost and process complexity increase

Engineering Contradiction:

Improvewavelength diversityVSAvoidmanufacturing efficiency

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

Multiple laser stripes requiring different epitaxial wafers are instead grown on a single epitaxial wafer. The wafer growth process creates multiple active regions with different compositions and wavelengths in one continuous process, eliminating the need for multiple separate wafer fabrication processes

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

Different regions of the single epitaxial wafer are engineered with local variations in material composition to create laser stripes with different emission wavelengths. Each stripe has tailored local properties (material composition, layer thickness) that determine its specific wavelength while all stripes are formed in one wafer

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If multiple laser stripes are included on a single chip with different wavelengths, then the wavelength range is improved, but the optical gain profile control becomes more challenging

Engineering Contradiction:

Improvewavelength rangeVSAvoidoptical gain profile control

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Each laser stripe region is engineered with specific local material properties including composition gradients, layer thickness variations, and intermixing depths that are tailored to achieve the desired optical gain profile for that particular wavelength. This localized engineering allows precise control of each stripe's optical characteristics

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The optical gain profiles of multiple laser stripes are controlled by varying key parameters during fabrication including intermixing depth, material composition ratios, and layer thicknesses. By changing these parameters across different stripe regions, distinct optical gain profiles are achieved for each wavelength while maintaining manufacturing control

Inventive Principle:

Principle #35Parameter changes

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 approach enables a semiconductor laser chip to emit light across a wide range of wavelengths with reduced complexity and cost by creating multiple laser stripes with varying optical gain profiles on a single epitaxial wafer, enhancing the system's versatility and efficiency.

Implementation Method 1

A laser stripe can be grown with an initial optical gain profile, and its optical gain profile can be shifted by using an intermixing process

Methodology Applied

Scientific EffectQuantum well intermixing:

Data Source

PatentUS11777279B2Laser architectures using quantum well intermixing techniques

Publication Date: 2023.10.03 APPLE INC

AI summary

A laser chip including a plurality of stripes is disclosed, where a laser stripe can be grown with an initial optical gain profile, and its optical gain profile can be shifted by using an intermixing process. In this manner, multiple laser stripes can be formed on the same laser chip from the same epitaxial wafer, where at least one laser stripe can have an optical gain profile shifted relative to another laser stripe. For example, each laser stripe can have a shifted optical gain profile relative to its neighboring laser stripe, thereby each laser stripe can emit light with a different range of wavelengths. The laser chip can emit light across a wide range of wavelengths. Examples of the disclosure further includes different regions of a given laser stripe having different intermixing amounts.