Dual-Section PPR PCSEL for High-Bandwidth Vertical Emission

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Solution Overview

Problem

Traditional photonic crystal surface-emitting lasers (PCSELs) face limitations in achieving high modulation bandwidths and stability over temperature and current, particularly in low-cost high-speed applications like optical data-center links, and alternative laser sources like edge emitters and coupled-cavity VCSELs have drawbacks such as requiring waveguides and poor beam quality.

Innovation Solution

A photon-photon resonance (PPR) PCSEL architecture with two photonic crystal designs is introduced, where the inner crystal optimizes vertical light emission and the outer crystal provides frequency response and lateral confinement, enabling direct modulation and higher bandwidths without waveguides.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If traditional PCSEL architecture is used, then manufacturing simplicity and beam quality are maintained, but modulation bandwidth is limited

Engineering Contradiction:
Improvemodulation bandwidthVSAvoidphotonic crystal structure
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The photonic crystal structure is segmented into two distinct sections: an inner photonic crystal section and an outer photonic crystal section. Each section has different etched patterns optimized for specific functions, allowing the device to achieve high modulation bandwidth through photon-photon resonance while maintaining vertical emission and lateral confinement properties

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the photonic crystal structure are given different local properties through distinct etched patterns. The inner section is optimized for vertical light emission while the outer section is optimized for frequency response and lateral confinement, enabling each region to contribute specifically to achieving high modulation bandwidth

Inventive Principle:
Principle #3Local quality

2Speed

If coupled-cavity VCSEL is used, then higher bandwidth is achieved, but stability over temperature and current deteriorates

Engineering Contradiction:
ImprovebandwidthVSAvoidtemperature and current stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The outer photonic crystal section provides optical feedback that creates photon-photon resonance with the inner section. This feedback mechanism stabilizes the laser operation over temperature and current variations while maintaining high bandwidth performance, eliminating the instability issues of coupled-cavity VCSELs

Inventive Principle:
Principle #23Feedback

3Speed

If edge emitter is used, then higher speeds are achieved, but beam quality and manufacturing cost deteriorate

Engineering Contradiction:
Improvemodulation speedVSAvoidwafer level testing capability
Core Design Contradiction:
SpeedVSEase of manufacture

Solution Approach 1:

Instead of using edge-emitting geometry, the patent inverts the approach by using vertical-cavity surface-emitting laser architecture with a novel dual-section photonic crystal design. This inversion maintains the manufacturing advantages of vertical emission (wafer-level testing, no dicing required) while achieving high speeds through photon-photon resonance

Inventive Principle:
Principle #13The other way round (Inversion)

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 PPR PCSEL achieves increased modulation bandwidth and stability, suitable for high-speed data communication applications, including data center links, with improved beam quality and cost-effective wafer-level testing.

Implementation Method 1

a first photonics crystal section operable to out-couple light in a vertical direction

Methodology Applied
Scientific EffectPhotonic crystal: Photonic Crystal

Implementation Method 2

a second photonics crystal section operable to produce a photon-photon resonance in a horizontal direction

Methodology Applied
Scientific EffectPhoton-photon resonance: Resonance

Data Source

PatentEP4664691A1Photon-photon resonance pcsel for high-speed applications
Publication Date: 2025.12.17 II VI DELAWARE INC
  • EP4664691A1 patent drawingFigure 1
  • EP4664691A1 patent drawingFigure 2A
  • EP4664691A1 patent drawingFigure 2B

AI summary

This disclosure describes a photon-photon resonance photonic crystal surface-emitting laser (PPR PCSEL) operable in high-speed applications. The PPR PCSEL comprises a first photonics crystal section and a second photonics crystal section located at along the same fabrication layer. The first photonics crystal section is operable to out-couple light vertically. The second photonics crystal section is operable to produce a photon-photon resonance. The etched pattern in the first photonics crystal section is different than the etched pattern in the second photonics crystal section.