Surface Emitting Semiconductor Laser Cavity Extending Region

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Solution Overview

Problem

Surface emitting semiconductor lasers with extended cavity structures face challenges in maintaining single-mode operation while increasing oxide aperture diameter, leading to unstable high-power output due to switching between longitudinal modes.

Innovation Solution

Incorporating a cavity extending region with an optical loss causing layer at specific nodes of standing waves in the extended cavity structure, which increases loss for unnecessary longitudinal modes and reduces loss for the desired mode, thereby suppressing mode switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the oxide aperture diameter is increased to achieve higher optical power, then the power output is improved, but the stability of single-mode operation deteriorates due to switching between longitudinal modes

Engineering Contradiction:

Improveoptical powerVSAvoidstability of single-mode operation

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent introduces an optical loss causing layer at specific positions (node positions) within the cavity extending region. This creates local optical loss only at specific locations rather than uniformly throughout the cavity, allowing selective suppression of unwanted longitudinal modes while maintaining the desired mode's oscillation, thus enabling stable single-mode operation at higher powers

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent modifies the cavity structure by extending the cavity length and introducing an optical loss causing layer, which changes the optical parameters of the laser cavity. This alters the loss characteristics for different longitudinal modes, creating a parameter difference that stabilizes single-mode operation even with larger oxide aperture diameters

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the cavity length is extended to suppress longitudinal modes, then the single-mode operation is improved, but the device complexity increases

Engineering Contradiction:

Improvesingle-mode operation stabilityVSAvoidcavity structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the cavity into distinct functional regions: the original cavity region and the extended cavity region. The optical loss causing layer is positioned specifically within the extended region at node positions of unwanted modes, allowing selective mode suppression without requiring complete redesign of the entire cavity structure

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The optical loss causing layer acts as an intermediary element that selectively introduces loss for unwanted longitudinal modes. This layer is positioned at node positions where the desired mode has minimal intensity, thereby suppressing unwanted modes without significantly affecting the desired mode's oscillation

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Enables stable single-mode operation at higher optical powers by selectively increasing loss for unwanted longitudinal modes, preventing mode hopping and achieving higher optical power without switching.

Implementation Method 1

The cavity extending region includes an optical loss causing layer at the position of at least one node of a standing wave of a selected longitudinal mode

Methodology Applied

Scientific EffectOptical absorption: Absorption (EM radiation)

Implementation Method 2

The first semiconductor multilayer reflector is formed on the substrate, and includes laminated pairs of a high refractive index layer having a relatively high refractive index and a low refractive index layer having a relatively low refractive index

Methodology Applied

Scientific EffectOptical reflection: Reflection

Data Source

PatentUS9219349B2Surface emitting semiconductor laser, surface emitting semiconductor laser device, optical transmission device, and information processing apparatus

Publication Date: 2015.12.22 FUJIFILM BUSINESS INNOVATION CORP

AI summary

A surface emitting semiconductor laser includes: a substrate; a first semiconductor multilayer reflector on the substrate including laminated pairs of a high refractive index layer relatively high in refractive index and a low refractive index layer relatively low in refractive index; an active region on or above the first reflector; a second semiconductor multilayer reflector on or above the active region including laminated pairs of a high refractive index layer relatively high in refractive index and a low refractive index layer relatively low in refractive index; and a cavity extending region formed between the first reflector and the active region or between the second reflector and the active region, having an optical film thickness greater than an oscillation wavelength, extending a cavity length, including a conductive semiconductor material, and including an optical loss causing layer at at least one node of a standing wave of a selected longitudinal mode.