Optical Bench Subassembly Prealignment for Photonic Devices

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Solution Overview

Problem

Current optical bench subassemblies face challenges in achieving efficient and reliable optical alignment of photonic devices with optical fibers, leading to high costs, low throughput, and package wastage due to stringent alignment requirements and sensitivity to thermal-mechanical deformations.

Innovation Solution

The integration of a photonic device with an optical bench in a subassembly allows for prealignment outside the optoelectronic package, using a base with precise grooves and reflective surfaces for passive or active alignment, and hermetic sealing, reducing the complexity and risk of the assembly process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If active optical alignment is used to align optical fibers with photonic devices, then alignment precision is improved, but device complexity and manufacturing cost increase due to requiring expensive alignment machinery and active testing equipment

Engineering Contradiction:
Improvealignment precisionVSAvoidalignment process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies preliminary action by pre-aligning the photonic device with the optical bench outside the hermetic package before final assembly. This pre-alignment process is performed using alignment fixtures and passive alignment methods, avoiding the need for expensive active alignment machinery inside the package. The photonic device is temporarily removed from the hermetic package, aligned with the optical bench using alignment marks and fixtures, and then reinstalled, thereby simplifying the overall alignment process and reducing manufacturing complexity.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If hermetic sealing is applied to protect optoelectronic devices from environment, then reliability is improved, but alignment precision deteriorates due to sensitivity to thermal-mechanical deformations

Engineering Contradiction:
Improveprotection from environmentVSAvoidalignment precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies segmentation by dividing the alignment process into two separate stages: (1) pre-alignment outside the hermetic package where the photonic device is aligned with the optical bench using alignment fixtures, and (2) final assembly where the hermetically sealed package is installed. This segmentation allows alignment to be performed when the components are not constrained by hermetic sealing, thereby maintaining alignment precision while still achieving environmental protection through hermetic sealing in the final assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent performs the alignment action preliminarily, before the hermetic sealing is applied. The photonic device is aligned with the optical bench while accessible from the outside, using alignment marks and fixtures. Only after alignment is achieved is the hermetic package sealed, preventing subsequent thermal-mechanical deformations from affecting the alignment. This preliminary alignment approach preserves both alignment precision and hermetic protection.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If photonic devices are aligned and assembled inside the hermetic package, then hermetic sealing is maintained, but productivity decreases due to difficulty in accessing and reworking components

Engineering Contradiction:
Improvehermetic sealing integrityVSAvoidassembly throughput
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent segments the manufacturing process into modular stages: (1) preparation of the hermetic package with optical bench and alignment fixtures, (2) removal of photonic devices from the sealed package for external alignment work, (3) alignment and testing outside the package, and (4) reinstallation and final sealing. This segmentation enables efficient alignment and testing operations to be performed outside the hermetic constraint, improving productivity while maintaining hermetic sealing integrity in the final product.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces alignment fixtures and alignment marks as intermediary elements that facilitate the alignment process. These intermediaries allow precise alignment to be achieved from the outside of the hermetic package without requiring complex internal alignment mechanisms or opening the hermetic seal during alignment. The alignment fixtures serve as mediators between the photonic device and the optical bench, enabling efficient alignment operations that improve productivity while preserving hermetic sealing.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 enhances alignment precision, reduces manufacturing costs, and increases the yield of optoelectronic packages by allowing functional testing of photonic devices before final assembly, while minimizing the impact of thermal-mechanical deformations.

Implementation Method 1

an optical element (e.g., a lens, a prism, a reflector, a mirror) for redirecting light from the optical fiber to a photonic device

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3274108A1Optical bench subassembly having integrated photonic device
Publication Date: 2018.01.31 NANOPRECISION PRODUCTS INC

AI summary

An optical bench subassembly including an integrated photonic device. Optical alignment of the photonic device with the optical bench can be performed outside of an optoelectronic package assembly before attaching thereto. The photonic device is attached to a base of the optical bench, with its optical input/output in optical alignment with the optical output/input of the optical bench. The optical bench supports an array of optical fibers in precise relationship to a structured reflective surface. The photonic device is mounted on a submount to be attached to the optical bench. The photonic device may be actively or passively aligned with the optical bench. After achieving optical alignment, the submount of the photonic device is fixedly attached to the base of the optical bench. The optical bench subassembly may be structured to be hermetically sealed as a hermetic feedthrough, to be hermetically attached to a hermetic optoelectronic package.