Nested Ring Resonators Suppress Higher-Order Lasing in Brillouin Lasers
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Solution Overview
Problem
Brillouin lasers in integrated photonics face challenges in suppressing higher-order lasing, as existing methods like Bragg gratings are imperfect and increase scattering loss, limiting the reduction in laser linewidth and requiring higher optical pump power.
Innovation Solution
An optical resonator device comprising a larger main waveguide ring resonator and one or more smaller nested waveguide ring resonators, where the smaller resonators introduce narrow-band loss to suppress higher-order lasing without significantly increasing the threshold of first-order stimulated Brillouin scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Bragg gratings are used to suppress higher-order lasing resonances, then higher-order lasing is suppressed, but scattering loss increases and threshold optical pump power increases
Solution Approach 1:
The patent implements nested ring resonators where smaller diameter ring resonators are positioned inside the larger diameter ring resonator. The smaller rings are nested within the area enclosed by the larger ring, creating a hierarchical structure that allows selective suppression of higher-order lasing modes through coupled resonance interactions without introducing scattering loss from gratings.
Solution Approach 2:
The patent applies different resonance characteristics to different regions of the resonator system. Each ring resonator is designed with specific diameter and resonance frequency to target particular lasing modes. The smaller rings have resonances tuned to suppress specific higher-order modes locally, while the larger ring provides the overall lasing cavity, creating spatially differentiated functional zones.
2Reliability
If Bragg gratings are used to suppress higher-order lasing resonances, then higher-order lasing is suppressed, but threshold optical pump power increases
Solution Approach 1:
The nested ring resonator configuration enables multiple resonance modes to interact through evanescent coupling. The smaller nested rings provide additional degrees of freedom for controlling which modes are suppressed, allowing the system to achieve higher-order lasing suppression with lower pump power thresholds compared to grating-based approaches.
Solution Approach 2:
The patent varies the diameters, positions, and coupling strengths of the nested ring resonators to optimize the suppression of higher-order modes. By adjusting these geometric parameters, the system can achieve effective mode suppression at lower optical pump power levels, avoiding the increased threshold power associated with Bragg grating methods.
3Loss of energy
If nested ring resonators are used to suppress higher-order lasing, then scattering loss is reduced, but device complexity increases
Solution Approach 1:
While the nested structure does increase geometric complexity, it eliminates the need for fabricating Bragg gratings, which require precise periodic modulation of the waveguide structure. The nested ring configuration, though multi-component, uses standard waveguide fabrication techniques and provides superior tolerance to manufacturing variations, effectively trading structural complexity for fabrication simplicity and reduced scattering loss.
4Reliability
If nested ring resonators are used to suppress higher-order lasing, then robustness to device imperfections is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
Each ring resonator in the nested structure can be independently designed with specific resonance frequencies and coupling characteristics. This local differentiation allows the system to maintain robustness against global fabrication imperfections, as each component can be optimized for its specific function and the overall system benefits from the distributed nature of the nested configuration.
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 effectively suppresses higher-order lasing in Brillouin lasers, enhancing robustness to device imperfections and maintaining low optical pump power requirements, while allowing for precise control of resonance suppression.
Implementation Method 1
The one or more second waveguide ring resonators optically communicate with the first waveguide ring resonator, such that an optical signal in the first waveguide ring resonator optically couples into the one or more second waveguide ring resonators
Implementation Method 2
The one or more second waveguide ring resonators is configured such that when the optical signal resonates within the first waveguide ring resonator and the one or more second waveguide ring resonators, the optical signal within the first waveguide ring resonator is suppressed
Implementation Method 3
Brillouin lasers typically exhibit higher-order lasing beyond certain power thresholds
Data Source
AI summary
An optical resonator device, which can be implemented in a Brillouin laser, comprises a first waveguide ring resonator having a first diameter, and one or more second waveguide ring resonators adjacent to the first waveguide ring resonator. The one or more second waveguide ring resonators each have a second diameter that is less than the first diameter. The one or more second waveguide ring resonators optically communicate with the first waveguide ring resonator, such that an optical signal in the first waveguide ring resonator optically couples into the one or more second waveguide ring resonators. The one or more second waveguide ring resonators is configured such that when the optical signal resonates within the first waveguide ring resonator and the one or more second waveguide ring resonators, the optical signal within the first waveguide ring resonator is suppressed.