Optical Waveguide Ring Resonator with TIR Mirrors and Active Element
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Solution Overview
Problem
Integrating intracavity active elements into optical ring resonators faces challenges such as achieving sufficient coupling with optical signals and selecting materials that are compatible for both the waveguide and active elements, with silicon being a desirable but inadequate material for active elements due to its indirect band gap.
Innovation Solution
An optical resonator design featuring a closed loop of optical waveguide segments connected by total internal reflection (TIR) mirrors and a photo-tunneling input/output port, with an intracavity active element optically coupled to the waveguide segments, allowing for efficient signal propagation, amplification, and modulation, and enabling compact, space-efficient fabrication on semiconductor substrates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If silicon is used as the material for the optical waveguide, then the cost is reduced and fabrication is simplified, but the material is incompatible for constructing active optical elements due to its indirect band gap
Solution Approach 1:
The optical resonator is divided into distinct segments: silicon-based passive waveguide segments for low-cost fabrication and III-V compound semiconductor segments for active optical element integration. This segmentation allows each segment to be optimized for its specific function while maintaining overall system integration.
Solution Approach 2:
The patent employs composite material structures combining silicon with III-V compound semiconductors (such as InGaAsP or GaAs) to create an integrated optical resonator. The III-V segments provide direct band gap properties suitable for active elements while the silicon segments provide low-loss waveguiding, achieving material compatibility for both passive and active functions.
2Reliability
If an intracavity active element is integrated into the optical ring resonator, then cavity enhancement of functionality is achieved, but sufficient coupling between the active element and optical signal is difficult to achieve
Solution Approach 1:
The active element is positioned at a specific location within the resonator where the optical field intensity is maximized, such as at regions of high curvature or specific geometric features. This local optimization ensures maximum coupling between the optical signal and the active element, enhancing modulation depth and functional performance.
Solution Approach 2:
The intracavity active element is integrated within the resonator cavity structure, with the active element physically nested within or adjacent to the waveguide path. This nesting arrangement ensures that the optical signal passes through or interacts with the active element, maximizing coupling efficiency while maintaining the compact resonator structure.
3Volume of moving object
If the optical waveguide segments are arranged as a closed loop with TIR mirrors, then compact fabrication is enabled, but optical loss may increase due to multiple reflection interfaces
Solution Approach 1:
The TIR mirror interfaces are integrated directly into the waveguide structure itself, eliminating the need for separate mirror components and reducing the number of discrete reflection interfaces. The waveguide geometry is designed to provide TIR at internal boundaries, merging the guiding and reflecting functions into a single integrated structure that minimizes optical loss.
Solution Approach 2:
The patent accepts minimal optical loss at the TIR interfaces as an acceptable trade-off for achieving compact fabrication, using standard semiconductor fabrication processes that are well-established and cost-effective. The loss is managed through optimized waveguide design rather than eliminating the compact structure.
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 design achieves low optical loss, efficient signal processing, and compact fabrication, facilitating integration with other photonic components while overcoming material compatibility issues and enhancing coupling efficiency.
Implementation Method 1
The optical resonator further comprises a plurality of total internal reflection (TIR) mirrors. A number of TIR mirrors in the plurality of TIR mirrors is equal to a number of segments in the plurality of segments. The plurality of segments of the optical waveguide is arranged as a closed loop wherein successive pairs of the segments are connected to one another at respective segment ends by successive ones of the TIR mirrors.
Implementation Method 2
The optical resonator further comprises a photo-tunneling input/output (I/O) port. The photo-tunneling I/O port comprises a designated TIR mirror of the successive TIR mirrors of the plurality of TIR mirrors.
Implementation Method 3
The intracavity active element overlies and is optically coupled to a designated segment of the plurality of segments.
Data Source
AI summary
An optical resonator, a photonic system and a method of optical resonance employ optical waveguide segments connected together with total internal reflection (TIR) mirrors to form a closed loop. The optical resonator includes the optical waveguide segments, an intracavity active element coupled to a designated one of the optical waveguide segments, the TIR mirrors and a photo-tunneling input/output (I/O) port. The photo-tunneling I/O port includes one of the TIR mirrors. The method includes propagating and reflecting the optical signal, or a portion thereof, in the optical resonator, transmitting a portion of the optical signal through the I/O port, and influencing the optical signal. The photonic system includes the optical resonator with optical gain and a source of an optical signal.