Heterogeneous Illuminator Butt-Coupling for Efficient Waveguide Transfer
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Solution Overview
Problem
Current photonic integrated circuits (PICs) face challenges with indirect bandgap materials like silicon, which require precise alignment and are costly, and have limitations in wavelength range, thermal stability, and optical power handling, especially when using dissimilar materials like silicon and GaAs or InP, leading to inefficiencies in power transfer and increased packaging costs.
Innovation Solution
A heterogeneously integrated illuminator using dissimilar materials with a butt-coupling mode-converter approach, allowing for efficient optical coupling without the need for extremely small taper widths, and utilizing waveguide materials that can be precisely patterned and etched, enabling operation across a broad wavelength range from UV to MIR and incorporating direct electrically-pumped semiconductor sources, amplifiers, and modulators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If taper coupling is used to transfer optical signal between dissimilar materials, then power transfer efficiency is improved, but manufacturing complexity and cost increase due to extremely small taper tip widths required
Solution Approach 1:
The patent introduces an intermediate layer with refractive index between the first and second materials to facilitate optical coupling. This intermediate layer acts as a mediator that enables efficient power transfer without requiring extremely small taper tip widths, thus resolving the contradiction between power transfer efficiency and manufacturing complexity
Solution Approach 2:
The patent changes the refractive index parameter by introducing an intermediate layer with a specific refractive index value between the two dissimilar materials. This parameter change enables adiabatic mode transformation and efficient coupling without the need for prohibitively small dimensions
2Adaptability or versatility
If precise alignment of separately processed chips is used, then integration of dissimilar materials is achieved, but packaging cost increases and scaling is limited
Solution Approach 1:
The patent merges the processing of dissimilar materials by bonding them together and then processing the bonded result to define waveguides and components. This combining approach eliminates the need for precise alignment during assembly, reduces packaging costs, and enables mass fabrication
Solution Approach 2:
The patent performs material bonding before defining the waveguides and other components of interest. This preliminary action allows for subsequent processing steps to be performed on the bonded structure as a whole, avoiding the need for precise alignment during final assembly
3Adaptability or versatility
If conventional waveguide materials like InP or silicon are used, then current needs are addressed, but wavelength range is limited by material absorption and thermal stability is reduced
Solution Approach 1:
The patent uses a composite structure combining different materials (first material, intermediate layer, second material) where each material is selected for its specific properties. This composite approach enables broad wavelength range operation from UV to mid-infrared while maintaining high thermal stability and power handling capability
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 solution enables high-performance illuminators with improved uniformity, reduced size, weight, and cost, and scalable manufacturing, suitable for next-generation sensors in fields like augmented reality, machine vision, and healthcare, with enhanced light shaping and power handling capabilities.
Implementation Method 1
To transfer the optical signal between dissimilar materials, the heterogeneous approach utilizes tapers whose dimensions are gradually reduced until the effective mode refractive indexes of dissimilar materials match and there is efficient power transfer
Implementation Method 2
employing butt-coupling in combination with a mode-converter to allow the heterogenous process to be used without the need for extremely small taper widths
Implementation Method 3
utilizing widely transparent materials and waveguides to guide, split and shape the light
Data Source
AI summary
A device comprises at least one of first, second and third elements fabricated on a common substrate. At least one of the first elements comprises an active waveguide structure and optical sources supporting an active optical mode and defined by at least one etch after attachment to the common substrate. At least one of the second elements comprises a passive waveguide structure supporting a passive optical mode, also comprising at least one of the one splitter structure and two emitter structures. At least one of the third elements, at least partly butt-coupled to at least one of the first elements, comprises an intermediate waveguide structure supporting intermediate optical modes. Mutual alignments of the first, second and third elements are defined using lithographic alignment marks that facilitate precise alignment between layers formed during processing steps of fabricating the first, the second and the third elements on a common substrate.