Folded Cavity Optoelectronic Device Waveguide Alignment
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Solution Overview
Problem
Existing optoelectronic devices lack efficient methods for precision cleaving and alignment of waveguides to achieve low-loss optical coupling and hybrid integration, particularly in semiconductor optical amplifiers, which limits their performance and packaging efficiency.
Innovation Solution
A semiconductor optoelectronic device with a folded cavity design using precision cleaving and etched features to align waveguides at a specific angle, allowing for single-sided alignment and coating with wavelength or polarization selective films to enhance optical properties, enabling effective light reflection and reduced residual reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional cleaving methods are used for waveguide alignment, then manufacturing is simpler, but alignment precision and optical coupling efficiency deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-defining etch features in the waveguide layer that serve as cleave initiators before the actual cleaving process. These etch features are positioned at precise locations to guide the cleave plane, ensuring accurate waveguide alignment and facet positioning before the mechanical cleaving step occurs.
Solution Approach 2:
The patent uses etch features as an intermediary element between the manufacturing process and the final cleaved facet. These features act as a mediator that translates design specifications into precise physical cleave positions, enabling accurate alignment without requiring complex direct positioning methods.
2Ease of manufacture
If single-ended optical coupling is used, then packaging cost and time of flight are reduced, but alignment precision and optical coupling efficiency deteriorate
Solution Approach 1:
The patent defines etch features in the same waveguide layer and mask level as the waveguide core before fabrication completes. This preliminary definition of the cleave initiator position ensures that the subsequent cleave will occur at the precise location needed for optimal optical coupling, achieving sub-micron tolerance without complex post-fabrication alignment.
Solution Approach 2:
The device structure itself provides the alignment function through the integrated etch feature that is part of the waveguide layer. The cleave initiator is self-aligned to the waveguide core through the fabrication process, eliminating the need for separate alignment mechanisms or procedures.
3Reliability
If folded cavity design with angled waveguides is used, then optical performance is enhanced, but device complexity and fabrication difficulty increase
Solution Approach 1:
The patent employs asymmetry by positioning the etch feature to create a specific angled configuration where the first waveguide meets the facet at a different angle than the second waveguide. This asymmetric arrangement enables the folded cavity design with precise angle control for optimized optical performance while using standard fabrication techniques.
Solution Approach 2:
The patent introduces dimensional complexity by creating a folded cavity structure where waveguides bend at angles rather than proceeding linearly. The etch feature enables this three-dimensional waveguide configuration within a planar fabrication process, achieving enhanced optical performance through spatial reconfiguration.
4Manufacturing precision
If precision cleaving with sub-micron tolerance is achieved, then optical coupling efficiency is improved, but manufacturing complexity and process control difficulty increase
Solution Approach 1:
The etch feature serves as an intermediary that translates standard fabrication capabilities into sub-micron precision cleave positioning. By using the etch feature as a physical reference point that is easily identifiable during cleaving, the process achieves high precision without requiring advanced process control systems.
Solution Approach 2:
The fabrication process itself creates the precision reference (etch feature) that enables accurate cleaving. The same lithography and etching steps that define the waveguide also define the cleave initiator position, allowing the process to self-align and achieve sub-micron tolerance through inherent process geometry rather than external measurement and adjustment.
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 low-loss optical modification, cost-effective packaging, and improved optical performance by ensuring precise alignment and coating of waveguides, facilitating hybrid integration and reduced time of flight in bit-serial optical processing.
Implementation Method 1
light travelling along the first waveguide is reflected into the second waveguide by the first facet
Data Source
AI summary
An optoelectronic device has at least a first facet (S), a first waveguide (2) and a second waveguide (3). The waveguides are substantially coincident at the first facet (6), such that light travelling along the first waveguide (2) is reflected into the second waveguide (3) by the first facet (6). The first facet (6) is formed by precision cleaving. Preferably an etch feature is incorporated in the same mask level as that to define the waveguide core.