Piezo-Tuned Optical Resonator With Mechanical Mode Suppression

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Solution Overview

Problem

Integrated photonic devices face challenges in achieving high frequency agility due to limited rapid frequency tuning of resonators, which affects laser linewidth narrowing while maintaining a long photon lifetime.

Innovation Solution

A photonic resonator device with a piezo-based optical tuning mechanism that applies stress-optical effects for high tuning bandwidth, incorporating a piezo actuator monolithically integrated with the optical resonator and waveguide on a common substrate, along with mechanical mode suppression means to minimize actuation-induced oscillations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If piezoelectric actuation is used to tune the resonator frequency, then frequency agility is improved, but mechanical oscillations and noise are introduced

Engineering Contradiction:

Improvefrequency agilityVSAvoidmechanical oscillations

Core Design Contradiction:

Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The patent introduces an acoustic matching layer as an intermediary between the piezoelectric actuator and the silicon nitride resonator. This layer acts as a mechanical impedance matcher that couples the acoustic waves from the piezoelectric actuator to the resonator mode, enabling efficient frequency tuning while suppressing unwanted mechanical oscillations and noise through optimized acoustic impedance matching.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If the resonator cavity is made longer to reduce phase noise, then laser linewidth is improved, but frequency tuning bandwidth is limited

Engineering Contradiction:

Improvephase noiseVSAvoidfrequency tuning bandwidth

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces conventional mechanical tuning methods with piezoelectric actuation that generates acoustic waves. This substitution enables rapid electronic control of the resonator frequency through voltage-driven acoustic modulation, achieving wide frequency tuning bandwidth without physically altering the resonator cavity length, thus maintaining low phase noise while enabling agile frequency tuning.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If monolithic integration is used to simplify manufacturing, then device complexity is reduced, but frequency tuning capability is limited

Engineering Contradiction:

Improvemonolithic integrationVSAvoidfrequency tuning capability

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent integrates multiple functions into a single monolithic device: the silicon nitride resonator provides both the optical resonance function and the mechanical acoustic resonance function, while the piezoelectric actuator serves as both the frequency tuning actuator and the acoustic wave source. This multi-functionality enables rapid frequency tuning capability within a monolithically integrated structure, combining manufacturing simplicity with tuning agility.

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 solution enables a compact, high-frequency agile photonic resonator with low noise applications, suitable for FMCW LiDAR and microwave photonics, by achieving geometric deformation of the resonator for frequency modulation while maintaining low noise and tight frequency locking.

Implementation Method 1

at least one piezo actuator to apply mechanical stress at least partially onto the at least one optical resonator

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Implementation Method 2

a stress-optical actuation in a monolithic integration

Methodology Applied

Scientific EffectStress-optical effect: Photoelasticity

Data Source

PatentUS20240302682A1Electrically tunable optical resonator on a chip for fast tunable integrated lasers

Publication Date: 2024.09.12 PURDUE RES FOUND

AI summary

The present invention relates to an electrically tunable photonic resonator device for a component having a fast and flat actuation response. The photonic resonator device includes at least one optical waveguide with an optical interface for coupling in laser light. The photonic resonator device includes at least one optical resonator including a waveguide made of an optical resonator material. A laser light coupled via the optical waveguide is coupled into at least one optical resonator. The photonic resonator device includes at least one piezo actuator to apply mechanical stress onto the optical resonator. The optical resonator, the piezo actuator, and the optical waveguide are monolithically integrated on a common substrate of the photonic resonator device. The photonic resonator device includes a mechanical mode suppression means configured to attenuate one or more mechanical modes of oscillation caused by an AC operation of the piezo actuator.