Tunable VCSEL With Flexible Mirror For Wavelength Adjustment

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Solution Overview

Problem

Traditional monolithic VCSEL arrays emit at the same wavelength, limiting their ability to meet the increasing demands of optical communication bandwidth due to insufficient variation in emission wavelength, which is insufficient for reliable high-speed data transmission.

Innovation Solution

A tunable VCSEL with an Indium phosphide-based active region and an overgrown tunnel junction, featuring a flexible output coupling mirror and a tuning cavity, allows for adjustable emission wavelength by applying a tuning voltage, enabling emission across a range of 1200 nm to 1900 nm and supporting high-speed data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional VCSEL arrays use fixed thickness epitaxial layers, then manufacturing is simplified, but emission wavelength variation is insufficient for high-speed optical communication

Engineering Contradiction:

Improveemission wavelength variationVSAvoidcavity length adjustment mechanism

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transforms the static VCSEL cavity into a dynamic structure by introducing a flexible output coupling mirror that can be actuated by a tuning electrode. This allows the cavity length to be adjusted dynamically after manufacturing, enabling wavelength tuning without requiring multiple fixed-cavity devices. The flexible mirror responds to electrical signals, making the cavity length adaptable while maintaining a relatively simple overall device structure.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the physical parameter of cavity length from a fixed manufacturing parameter to a可调 operational parameter. By introducing the flexible output coupling mirror and tuning electrode, the cavity length can be varied electrically to tune the emission wavelength across a range sufficient for WDM applications, thereby changing a static parameter into a dynamic control variable.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If VCSEL emission wavelength is tuned by temperature variation, then device structure remains simple, but wavelength spread is insufficient for reliable high-speed data transmission

Engineering Contradiction:

Improvewavelength tuning rangeVSAvoidoptical communication reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces the thermal tuning mechanism with an electro-mechanical actuation system. Instead of heating or cooling the VCSEL to change wavelength, a tuning electrode applies electrical force to deflect the flexible output coupling mirror, mechanically adjusting the cavity length. This substitution provides more precise and reliable wavelength control without the thermal management complexity and insufficient tuning range of temperature-based methods.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If multiple VCSELs emit at the same wavelength, then manufacturing consistency is maintained, but bandwidth capacity is limited

Engineering Contradiction:

Improveoptical communication bandwidthVSAvoidwavelength multiplexing capability

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent makes each VCSEL in the array multi-functional by equipping them with identical flexible output coupling mirrors and tuning electrodes. This allows any VCSEL to be tuned to any wavelength within the tuning range, enabling the array to function as a reconfigurable wavelength-division multiplexing system. Each device can adapt its emission wavelength dynamically, providing universal wavelength assignment capability across the entire array for high-capacity optical communication.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 tunable VCSEL achieves wavelength tuning up to 100 nm, enabling multi-beam emission devices to transmit data at rates exceeding 50 Gb/s, surpassing the limitations of traditional VCSELs in high-speed fiber optic communication systems.

Implementation Method 1

application of a tuning voltage to a tuning electrode affixed to and/or deposited on a flexible output coupling mirror of the VCSEL such that the flexible coupling mirror flexes

Methodology Applied

Scientific EffectElectrostatic actuation: Electrostatics

Implementation Method 2

VCSEL cavity having an adjustable length... active region material structure comprising the active region and the tunnel junction of the VCSEL

Methodology Applied

Scientific EffectLight emission from semiconductor active region: Electroluminescence

Data Source

PatentUS10601201B1Tunable vertical-cavity surface-emitting laser

Publication Date: 2020.03.24 MELLANOX TECHNOLOGIES LTD(IL)

AI summary

A vertical cavity surface emitting laser (VCSEL) array is provided. Each tunable VCSEL includes an output coupling mirror; a high reflectivity mirror; an active cavity material structure disposed between the output coupling mirror and the high reflectivity mirror; and a spacer layer disposed between the output coupling mirror and the active cavity material. A tuning cavity is defined within the spacer layer. Each VCSEL further includes a first contact pad and a second contact pad designed to receive a driving voltage; a tuning electrode on a first surface of the output coupling mirror for tuning the emission wavelength to a distinct wavelength.